refactor(expirymap): optimize performance and add StopCleaner method

Move tracking of the last SMART data fetch from individual System
instances to the SystemManager using a TTL-based ExpiryMap.

This ensures that the SMART_INTERVAL is respected even if an
agent connection is dropped and re-established, preventing
redundant data collection on every reconnect.

agent/agent.go

@@ -6,7 +6,6 @@ package agent
 
 import (
 	"log/slog"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -14,6 +13,7 @@ import (
 	"github.com/gliderlabs/ssh"
 	"github.com/henrygd/beszel"
 	"github.com/henrygd/beszel/agent/deltatracker"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/common"
 	"github.com/henrygd/beszel/internal/entities/system"
 	gossh "golang.org/x/crypto/ssh"
@@ -68,11 +68,11 @@ func NewAgent(dataDir ...string) (agent *Agent, err error) {
 		slog.Info("Data directory", "path", agent.dataDir)
 	}
 
-	agent.memCalc, _ = GetEnv("MEM_CALC")
+	agent.memCalc, _ = utils.GetEnv("MEM_CALC")
 	agent.sensorConfig = agent.newSensorConfig()
 
 	// Parse disk usage cache duration (e.g., "15m", "1h") to avoid waking sleeping disks
-	if diskUsageCache, exists := GetEnv("DISK_USAGE_CACHE"); exists {
+	if diskUsageCache, exists := utils.GetEnv("DISK_USAGE_CACHE"); exists {
 		if duration, err := time.ParseDuration(diskUsageCache); err == nil {
 			agent.diskUsageCacheDuration = duration
 			slog.Info("DISK_USAGE_CACHE", "duration", duration)
@@ -82,7 +82,7 @@ func NewAgent(dataDir ...string) (agent *Agent, err error) {
 	}
 
 	// Set up slog with a log level determined by the LOG_LEVEL env var
-	if logLevelStr, exists := GetEnv("LOG_LEVEL"); exists {
+	if logLevelStr, exists := utils.GetEnv("LOG_LEVEL"); exists {
 		switch strings.ToLower(logLevelStr) {
 		case "debug":
 			agent.debug = true
@@ -103,7 +103,7 @@ func NewAgent(dataDir ...string) (agent *Agent, err error) {
 	agent.refreshSystemDetails()
 
 	// SMART_INTERVAL env var to update smart data at this interval
-	if smartIntervalEnv, exists := GetEnv("SMART_INTERVAL"); exists {
+	if smartIntervalEnv, exists := utils.GetEnv("SMART_INTERVAL"); exists {
 		if duration, err := time.ParseDuration(smartIntervalEnv); err == nil && duration > 0 {
 			agent.systemDetails.SmartInterval = duration
 			slog.Info("SMART_INTERVAL", "duration", duration)
@@ -148,15 +148,6 @@ func NewAgent(dataDir ...string) (agent *Agent, err error) {
 	return agent, nil
 }
 
-// GetEnv retrieves an environment variable with a "BESZEL_AGENT_" prefix, or falls back to the unprefixed key.
-func GetEnv(key string) (value string, exists bool) {
-	if value, exists = os.LookupEnv("BESZEL_AGENT_" + key); exists {
-		return value, exists
-	}
-	// Fallback to the old unprefixed key
-	return os.LookupEnv(key)
-}
-
 func (a *Agent) gatherStats(options common.DataRequestOptions) *system.CombinedData {
 	a.Lock()
 	defer a.Unlock()
@@ -213,7 +204,7 @@ func (a *Agent) gatherStats(options common.DataRequestOptions) *system.CombinedD
 			data.Stats.ExtraFs[key] = stats
 			// Add percentages to Info struct for dashboard
 			if stats.DiskTotal > 0 {
-				pct := twoDecimals((stats.DiskUsed / stats.DiskTotal) * 100)
+				pct := utils.TwoDecimals((stats.DiskUsed / stats.DiskTotal) * 100)
 				data.Info.ExtraFsPct[key] = pct
 			}
 		}

agent/client.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/common"
 
 	"github.com/fxamacker/cbor/v2"
@@ -43,7 +44,7 @@ type WebSocketClient struct {
 // newWebSocketClient creates a new WebSocket client for the given agent.
 // It reads configuration from environment variables and validates the hub URL.
 func newWebSocketClient(agent *Agent) (client *WebSocketClient, err error) {
-	hubURLStr, exists := GetEnv("HUB_URL")
+	hubURLStr, exists := utils.GetEnv("HUB_URL")
 	if !exists {
 		return nil, errors.New("HUB_URL environment variable not set")
 	}
@@ -72,12 +73,12 @@ func newWebSocketClient(agent *Agent) (client *WebSocketClient, err error) {
 // If neither is set, it returns an error.
 func getToken() (string, error) {
 	// get token from env var
-	token, _ := GetEnv("TOKEN")
+	token, _ := utils.GetEnv("TOKEN")
 	if token != "" {
 		return token, nil
 	}
 	// get token from file
-	tokenFile, _ := GetEnv("TOKEN_FILE")
+	tokenFile, _ := utils.GetEnv("TOKEN_FILE")
 	if tokenFile == "" {
 		return "", errors.New("must set TOKEN or TOKEN_FILE")
 	}
@@ -197,7 +198,7 @@ func (client *WebSocketClient) handleAuthChallenge(msg *common.HubRequest[cbor.R
 	}
 
 	if authRequest.NeedSysInfo {
-		response.Name, _ = GetEnv("SYSTEM_NAME")
+		response.Name, _ = utils.GetEnv("SYSTEM_NAME")
 		response.Hostname = client.agent.systemDetails.Hostname
 		serverAddr := client.agent.connectionManager.serverOptions.Addr
 		_, response.Port, _ = net.SplitHostPort(serverAddr)

agent/data_dir.go

@@ -6,6 +6,8 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+
+	"github.com/henrygd/beszel/agent/utils"
 )
 
 // GetDataDir returns the path to the data directory for the agent and an error
@@ -16,7 +18,7 @@ func GetDataDir(dataDirs ...string) (string, error) {
 		return testDataDirs(dataDirs)
 	}
 
-	dataDir, _ := GetEnv("DATA_DIR")
+	dataDir, _ := utils.GetEnv("DATA_DIR")
 	if dataDir != "" {
 		dataDirs = append(dataDirs, dataDir)
 	}

agent/disk.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 
 	"github.com/shirou/gopsutil/v4/disk"
@@ -37,7 +38,7 @@ func isDockerSpecialMountpoint(mountpoint string) bool {
 
 // Sets up the filesystems to monitor for disk usage and I/O.
 func (a *Agent) initializeDiskInfo() {
-	filesystem, _ := GetEnv("FILESYSTEM")
+	filesystem, _ := utils.GetEnv("FILESYSTEM")
 	efPath := "/extra-filesystems"
 	hasRoot := false
 	isWindows := runtime.GOOS == "windows"
@@ -141,7 +142,7 @@ func (a *Agent) initializeDiskInfo() {
 	}
 
 	// Add EXTRA_FILESYSTEMS env var values to fsStats
-	if extraFilesystems, exists := GetEnv("EXTRA_FILESYSTEMS"); exists {
+	if extraFilesystems, exists := utils.GetEnv("EXTRA_FILESYSTEMS"); exists {
 		for fsEntry := range strings.SplitSeq(extraFilesystems, ",") {
 			// Parse custom name from format: device__customname
 			fs, customName := parseFilesystemEntry(fsEntry)
@@ -412,12 +413,12 @@ func (a *Agent) updateDiskUsage(systemStats *system.Stats) {
 			continue
 		}
 		if d, err := disk.Usage(stats.Mountpoint); err == nil {
-			stats.DiskTotal = bytesToGigabytes(d.Total)
-			stats.DiskUsed = bytesToGigabytes(d.Used)
+			stats.DiskTotal = utils.BytesToGigabytes(d.Total)
+			stats.DiskUsed = utils.BytesToGigabytes(d.Used)
 			if stats.Root {
-				systemStats.DiskTotal = bytesToGigabytes(d.Total)
-				systemStats.DiskUsed = bytesToGigabytes(d.Used)
-				systemStats.DiskPct = twoDecimals(d.UsedPercent)
+				systemStats.DiskTotal = utils.BytesToGigabytes(d.Total)
+				systemStats.DiskUsed = utils.BytesToGigabytes(d.Used)
+				systemStats.DiskPct = utils.TwoDecimals(d.UsedPercent)
 			}
 		} else {
 			// reset stats if error (likely unmounted)
@@ -470,8 +471,8 @@ func (a *Agent) updateDiskIo(cacheTimeMs uint16, systemStats *system.Stats) {
 
 			diskIORead := (d.ReadBytes - prev.readBytes) * 1000 / msElapsed
 			diskIOWrite := (d.WriteBytes - prev.writeBytes) * 1000 / msElapsed
-			readMbPerSecond := bytesToMegabytes(float64(diskIORead))
-			writeMbPerSecond := bytesToMegabytes(float64(diskIOWrite))
+			readMbPerSecond := utils.BytesToMegabytes(float64(diskIORead))
+			writeMbPerSecond := utils.BytesToMegabytes(float64(diskIOWrite))
 
 			// validate values
 			if readMbPerSecond > 50_000 || writeMbPerSecond > 50_000 {

agent/docker.go

@@ -21,6 +21,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel/agent/deltatracker"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/container"
 
 	"github.com/blang/semver"
@@ -336,12 +337,12 @@ func validateCpuPercentage(cpuPct float64, containerName string) error {
 
 // updateContainerStatsValues updates the final stats values
 func updateContainerStatsValues(stats *container.Stats, cpuPct float64, usedMemory uint64, sent_delta, recv_delta uint64, readTime time.Time) {
-	stats.Cpu = twoDecimals(cpuPct)
-	stats.Mem = bytesToMegabytes(float64(usedMemory))
+	stats.Cpu = utils.TwoDecimals(cpuPct)
+	stats.Mem = utils.BytesToMegabytes(float64(usedMemory))
 	stats.Bandwidth = [2]uint64{sent_delta, recv_delta}
 	// TODO(0.19+): stop populating NetworkSent/NetworkRecv (deprecated in 0.18.3)
-	stats.NetworkSent = bytesToMegabytes(float64(sent_delta))
-	stats.NetworkRecv = bytesToMegabytes(float64(recv_delta))
+	stats.NetworkSent = utils.BytesToMegabytes(float64(sent_delta))
+	stats.NetworkRecv = utils.BytesToMegabytes(float64(recv_delta))
 	stats.PrevReadTime = readTime
 }
 
@@ -487,7 +488,7 @@ func (dm *dockerManager) deleteContainerStatsSync(id string) {
 
 // Creates a new http client for Docker or Podman API
 func newDockerManager() *dockerManager {
-	dockerHost, exists := GetEnv("DOCKER_HOST")
+	dockerHost, exists := utils.GetEnv("DOCKER_HOST")
 	if exists {
 		// return nil if set to empty string
 		if dockerHost == "" {
@@ -523,7 +524,7 @@ func newDockerManager() *dockerManager {
 
 	// configurable timeout
 	timeout := time.Millisecond * time.Duration(dockerTimeoutMs)
-	if t, set := GetEnv("DOCKER_TIMEOUT"); set {
+	if t, set := utils.GetEnv("DOCKER_TIMEOUT"); set {
 		timeout, err = time.ParseDuration(t)
 		if err != nil {
 			slog.Error(err.Error())
@@ -540,7 +541,7 @@ func newDockerManager() *dockerManager {
 
 	// Read container exclusion patterns from environment variable
 	var excludeContainers []string
-	if excludeStr, set := GetEnv("EXCLUDE_CONTAINERS"); set && excludeStr != "" {
+	if excludeStr, set := utils.GetEnv("EXCLUDE_CONTAINERS"); set && excludeStr != "" {
 		parts := strings.SplitSeq(excludeStr, ",")
 		for part := range parts {
 			trimmed := strings.TrimSpace(part)

agent/docker_test.go

@@ -18,6 +18,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel/agent/deltatracker"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/container"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -298,48 +299,6 @@ func TestUpdateContainerStatsValues(t *testing.T) {
 	assert.Equal(t, testTime, stats.PrevReadTime)
 }
 
-func TestTwoDecimals(t *testing.T) {
-	tests := []struct {
-		name     string
-		input    float64
-		expected float64
-	}{
-		{"round down", 1.234, 1.23},
-		{"round half up", 1.235, 1.24}, // math.Round rounds half up
-		{"no rounding needed", 1.23, 1.23},
-		{"negative number", -1.235, -1.24}, // math.Round rounds half up (more negative)
-		{"zero", 0.0, 0.0},
-		{"large number", 123.456, 123.46}, // rounds 5 up
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := twoDecimals(tt.input)
-			assert.Equal(t, tt.expected, result)
-		})
-	}
-}
-
-func TestBytesToMegabytes(t *testing.T) {
-	tests := []struct {
-		name     string
-		input    float64
-		expected float64
-	}{
-		{"1 MB", 1048576, 1.0},
-		{"512 KB", 524288, 0.5},
-		{"zero", 0, 0},
-		{"large value", 1073741824, 1024}, // 1 GB = 1024 MB
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := bytesToMegabytes(tt.input)
-			assert.Equal(t, tt.expected, result)
-		})
-	}
-}
-
 func TestInitializeCpuTracking(t *testing.T) {
 	dm := &dockerManager{
 		lastCpuContainer: make(map[uint16]map[string]uint64),
@@ -905,11 +864,11 @@ func TestContainerStatsEndToEndWithRealData(t *testing.T) {
 	updateContainerStatsValues(testStats, cpuPct, usedMemory, 1000000, 500000, testTime)
 
 	assert.Equal(t, cpuPct, testStats.Cpu)
-	assert.Equal(t, bytesToMegabytes(float64(usedMemory)), testStats.Mem)
+	assert.Equal(t, utils.BytesToMegabytes(float64(usedMemory)), testStats.Mem)
 	assert.Equal(t, [2]uint64{1000000, 500000}, testStats.Bandwidth)
 	// Deprecated fields still populated for backward compatibility with older hubs
-	assert.Equal(t, bytesToMegabytes(1000000), testStats.NetworkSent)
-	assert.Equal(t, bytesToMegabytes(500000), testStats.NetworkRecv)
+	assert.Equal(t, utils.BytesToMegabytes(1000000), testStats.NetworkSent)
+	assert.Equal(t, utils.BytesToMegabytes(500000), testStats.NetworkRecv)
 	assert.Equal(t, testTime, testStats.PrevReadTime)
 }
 
@@ -1190,13 +1149,13 @@ func TestConstantsAndUtilityFunctions(t *testing.T) {
 	assert.Equal(t, 5*1024*1024, maxTotalLogSize)               // 5MB
 
 	// Test utility functions
-	assert.Equal(t, 1.5, twoDecimals(1.499))
-	assert.Equal(t, 1.5, twoDecimals(1.5))
-	assert.Equal(t, 1.5, twoDecimals(1.501))
+	assert.Equal(t, 1.5, utils.TwoDecimals(1.499))
+	assert.Equal(t, 1.5, utils.TwoDecimals(1.5))
+	assert.Equal(t, 1.5, utils.TwoDecimals(1.501))
 
-	assert.Equal(t, 1.0, bytesToMegabytes(1048576)) // 1 MB
-	assert.Equal(t, 0.5, bytesToMegabytes(524288))  // 512 KB
-	assert.Equal(t, 0.0, bytesToMegabytes(0))
+	assert.Equal(t, 1.0, utils.BytesToMegabytes(1048576)) // 1 MB
+	assert.Equal(t, 0.5, utils.BytesToMegabytes(524288))  // 512 KB
+	assert.Equal(t, 0.0, utils.BytesToMegabytes(0))
 }
 
 func TestDecodeDockerLogStream(t *testing.T) {

agent/emmc_linux.go

@@ -8,6 +8,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/smart"
 )
 
@@ -141,9 +142,9 @@ func readEmmcHealth(blockName string) (emmcHealth, bool) {
 	out.lifeA = lifeA
 	out.lifeB = lifeB
 
-	out.model = readStringFile(filepath.Join(deviceDir, "name"))
-	out.serial = readStringFile(filepath.Join(deviceDir, "serial"))
-	out.revision = readStringFile(filepath.Join(deviceDir, "prv"))
+	out.model = utils.ReadStringFile(filepath.Join(deviceDir, "name"))
+	out.serial = utils.ReadStringFile(filepath.Join(deviceDir, "serial"))
+	out.revision = utils.ReadStringFile(filepath.Join(deviceDir, "prv"))
 
 	if capBytes, ok := readBlockCapacityBytes(blockName); ok {
 		out.capacity = capBytes
@@ -153,7 +154,7 @@ func readEmmcHealth(blockName string) (emmcHealth, bool) {
 }
 
 func readLifeTime(deviceDir string) (uint8, uint8, bool) {
-	if content, ok := readStringFileOK(filepath.Join(deviceDir, "life_time")); ok {
+	if content, ok := utils.ReadStringFileOK(filepath.Join(deviceDir, "life_time")); ok {
 		a, b, ok := parseHexBytePair(content)
 		return a, b, ok
 	}
@@ -170,7 +171,7 @@ func readBlockCapacityBytes(blockName string) (uint64, bool) {
 	sizePath := filepath.Join(emmcSysfsRoot, "class", "block", blockName, "size")
 	lbsPath := filepath.Join(emmcSysfsRoot, "class", "block", blockName, "queue", "logical_block_size")
 
-	sizeStr, ok := readStringFileOK(sizePath)
+	sizeStr, ok := utils.ReadStringFileOK(sizePath)
 	if !ok {
 		return 0, false
 	}
@@ -179,7 +180,7 @@ func readBlockCapacityBytes(blockName string) (uint64, bool) {
 		return 0, false
 	}
 
-	lbsStr, ok := readStringFileOK(lbsPath)
+	lbsStr, ok := utils.ReadStringFileOK(lbsPath)
 	logicalBlockSize := uint64(512)
 	if ok {
 		if parsed, err := strconv.ParseUint(lbsStr, 10, 64); err == nil && parsed > 0 {
@@ -191,7 +192,7 @@ func readBlockCapacityBytes(blockName string) (uint64, bool) {
 }
 
 func readHexByteFile(path string) (uint8, bool) {
-	content, ok := readStringFileOK(path)
+	content, ok := utils.ReadStringFileOK(path)
 	if !ok {
 		return 0, false
 	}

agent/file_utils.go

@@ -1,24 +0,0 @@
-package agent
-
-import (
-	"os"
-	"strings"
-)
-
-func readStringFile(path string) string {
-	content, _ := readStringFileOK(path)
-	return content
-}
-
-func readStringFileOK(path string) (string, bool) {
-	b, err := os.ReadFile(path)
-	if err != nil {
-		return "", false
-	}
-	return strings.TrimSpace(string(b)), true
-}
-
-func fileExists(path string) bool {
-	_, err := os.Stat(path)
-	return err == nil
-}

agent/gpu.go

@@ -15,6 +15,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 )
 
@@ -291,8 +292,8 @@ func (gm *GPUManager) parseAmdData(output []byte) bool {
 		}
 		gpu := gm.GpuDataMap[id]
 		gpu.Temperature, _ = strconv.ParseFloat(v.Temperature, 64)
-		gpu.MemoryUsed = bytesToMegabytes(memoryUsage)
-		gpu.MemoryTotal = bytesToMegabytes(totalMemory)
+		gpu.MemoryUsed = utils.BytesToMegabytes(memoryUsage)
+		gpu.MemoryTotal = utils.BytesToMegabytes(totalMemory)
 		gpu.Usage += usage
 		gpu.Power += power
 		gpu.Count++
@@ -366,16 +367,16 @@ func (gm *GPUManager) calculateGPUAverage(id string, gpu *system.GPUData, cacheK
 	gpuAvg := *gpu
 	deltaUsage, deltaPower, deltaPowerPkg := gm.calculateDeltas(gpu, lastSnapshot)
 
-	gpuAvg.Power = twoDecimals(deltaPower / float64(deltaCount))
+	gpuAvg.Power = utils.TwoDecimals(deltaPower / float64(deltaCount))
 
 	if gpu.Engines != nil {
 		// make fresh map for averaged engine metrics to avoid mutating
 		// the accumulator map stored in gm.GpuDataMap
 		gpuAvg.Engines = make(map[string]float64, len(gpu.Engines))
 		gpuAvg.Usage = gm.calculateIntelGPUUsage(&gpuAvg, gpu, lastSnapshot, deltaCount)
-		gpuAvg.PowerPkg = twoDecimals(deltaPowerPkg / float64(deltaCount))
+		gpuAvg.PowerPkg = utils.TwoDecimals(deltaPowerPkg / float64(deltaCount))
 	} else {
-		gpuAvg.Usage = twoDecimals(deltaUsage / float64(deltaCount))
+		gpuAvg.Usage = utils.TwoDecimals(deltaUsage / float64(deltaCount))
 	}
 
 	gm.lastAvgData[id] = gpuAvg
@@ -410,17 +411,17 @@ func (gm *GPUManager) calculateIntelGPUUsage(gpuAvg, gpu *system.GPUData, lastSn
 		} else {
 			deltaEngine = engine
 		}
-		gpuAvg.Engines[name] = twoDecimals(deltaEngine / float64(deltaCount))
+		gpuAvg.Engines[name] = utils.TwoDecimals(deltaEngine / float64(deltaCount))
 		maxEngineUsage = max(maxEngineUsage, deltaEngine/float64(deltaCount))
 	}
-	return twoDecimals(maxEngineUsage)
+	return utils.TwoDecimals(maxEngineUsage)
 }
 
 // updateInstantaneousValues updates values that should reflect current state, not averages
 func (gm *GPUManager) updateInstantaneousValues(gpuAvg *system.GPUData, gpu *system.GPUData) {
-	gpuAvg.Temperature = twoDecimals(gpu.Temperature)
-	gpuAvg.MemoryUsed = twoDecimals(gpu.MemoryUsed)
-	gpuAvg.MemoryTotal = twoDecimals(gpu.MemoryTotal)
+	gpuAvg.Temperature = utils.TwoDecimals(gpu.Temperature)
+	gpuAvg.MemoryUsed = utils.TwoDecimals(gpu.MemoryUsed)
+	gpuAvg.MemoryTotal = utils.TwoDecimals(gpu.MemoryTotal)
 }
 
 // storeSnapshot saves the current GPU state for this cache key
@@ -687,7 +688,7 @@ func (gm *GPUManager) resolveLegacyCollectorPriority(caps gpuCapabilities) []col
 	priorities := make([]collectorSource, 0, 4)
 
 	if caps.hasNvidiaSmi && !caps.hasTegrastats {
-		if nvml, _ := GetEnv("NVML"); nvml == "true" {
+		if nvml, _ := utils.GetEnv("NVML"); nvml == "true" {
 			priorities = append(priorities, collectorSourceNVML, collectorSourceNvidiaSMI)
 		} else {
 			priorities = append(priorities, collectorSourceNvidiaSMI)
@@ -695,7 +696,7 @@ func (gm *GPUManager) resolveLegacyCollectorPriority(caps gpuCapabilities) []col
 	}
 
 	if caps.hasRocmSmi {
-		if val, _ := GetEnv("AMD_SYSFS"); val == "true" {
+		if val, _ := utils.GetEnv("AMD_SYSFS"); val == "true" {
 			priorities = append(priorities, collectorSourceAmdSysfs)
 		} else {
 			priorities = append(priorities, collectorSourceRocmSMI)
@@ -728,7 +729,7 @@ func (gm *GPUManager) resolveLegacyCollectorPriority(caps gpuCapabilities) []col
 
 // NewGPUManager creates and initializes a new GPUManager
 func NewGPUManager() (*GPUManager, error) {
-	if skipGPU, _ := GetEnv("SKIP_GPU"); skipGPU == "true" {
+	if skipGPU, _ := utils.GetEnv("SKIP_GPU"); skipGPU == "true" {
 		return nil, nil
 	}
 	var gm GPUManager
@@ -745,7 +746,7 @@ func NewGPUManager() (*GPUManager, error) {
 	}
 
 	// if GPU_COLLECTOR is set, start user-defined collectors.
-	if collectorConfig, ok := GetEnv("GPU_COLLECTOR"); ok && strings.TrimSpace(collectorConfig) != "" {
+	if collectorConfig, ok := utils.GetEnv("GPU_COLLECTOR"); ok && strings.TrimSpace(collectorConfig) != "" {
 		priorities := parseCollectorPriority(collectorConfig)
 		if gm.startCollectorsByPriority(priorities, caps) == 0 {
 			return nil, fmt.Errorf("no configured GPU collectors are available")

agent/gpu_amd_linux.go

@@ -13,6 +13,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 )
 
@@ -144,8 +145,8 @@ func (gm *GPUManager) updateAmdGpuData(cardPath string) bool {
 	if usageErr == nil {
 		gpu.Usage += usage
 	}
-	gpu.MemoryUsed = bytesToMegabytes(memUsed)
-	gpu.MemoryTotal = bytesToMegabytes(memTotal)
+	gpu.MemoryUsed = utils.BytesToMegabytes(memUsed)
+	gpu.MemoryTotal = utils.BytesToMegabytes(memTotal)
 	gpu.Temperature = temp
 	gpu.Power += power
 	gpu.Count++

agent/gpu_amd_linux_test.go

@@ -7,6 +7,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -128,14 +129,14 @@ func TestUpdateAmdGpuDataWithFakeSysfs(t *testing.T) {
 		{
 			name:            "sums vram and gtt when gtt is present",
 			writeGTT:        true,
-			wantMemoryUsed:  bytesToMegabytes(1073741824 + 536870912),
-			wantMemoryTotal: bytesToMegabytes(2147483648 + 4294967296),
+			wantMemoryUsed:  utils.BytesToMegabytes(1073741824 + 536870912),
+			wantMemoryTotal: utils.BytesToMegabytes(2147483648 + 4294967296),
 		},
 		{
 			name:            "falls back to vram when gtt is missing",
 			writeGTT:        false,
-			wantMemoryUsed:  bytesToMegabytes(1073741824),
-			wantMemoryTotal: bytesToMegabytes(2147483648),
+			wantMemoryUsed:  utils.BytesToMegabytes(1073741824),
+			wantMemoryTotal: utils.BytesToMegabytes(2147483648),
 		},
 	}
 

agent/gpu_intel.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 )
 
@@ -52,7 +53,7 @@ func (gm *GPUManager) updateIntelFromStats(sample *intelGpuStats) bool {
 func (gm *GPUManager) collectIntelStats() (err error) {
 	// Build command arguments, optionally selecting a device via -d
 	args := []string{"-s", intelGpuStatsInterval, "-l"}
-	if dev, ok := GetEnv("INTEL_GPU_DEVICE"); ok && dev != "" {
+	if dev, ok := utils.GetEnv("INTEL_GPU_DEVICE"); ok && dev != "" {
 		args = append(args, "-d", dev)
 	}
 	cmd := exec.Command(intelGpuStatsCmd, args...)

agent/gpu_nvtop.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 )
 
@@ -80,10 +81,10 @@ func (gm *GPUManager) updateNvtopSnapshots(snapshots []nvtopSnapshot) bool {
 			gpu.Temperature = parseNvtopNumber(*sample.Temp)
 		}
 		if sample.MemUsed != nil {
-			gpu.MemoryUsed = bytesToMegabytes(parseNvtopNumber(*sample.MemUsed))
+			gpu.MemoryUsed = utils.BytesToMegabytes(parseNvtopNumber(*sample.MemUsed))
 		}
 		if sample.MemTotal != nil {
-			gpu.MemoryTotal = bytesToMegabytes(parseNvtopNumber(*sample.MemTotal))
+			gpu.MemoryTotal = utils.BytesToMegabytes(parseNvtopNumber(*sample.MemTotal))
 		}
 		if sample.GpuUtil != nil {
 			gpu.Usage += parseNvtopNumber(*sample.GpuUtil)

agent/gpu_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 
 	"github.com/stretchr/testify/assert"
@@ -265,8 +266,8 @@ func TestParseNvtopData(t *testing.T) {
 	assert.Equal(t, 48.0, g0.Temperature)
 	assert.Equal(t, 5.0, g0.Usage)
 	assert.Equal(t, 13.0, g0.Power)
-	assert.Equal(t, bytesToMegabytes(349372416), g0.MemoryUsed)
-	assert.Equal(t, bytesToMegabytes(4294967296), g0.MemoryTotal)
+	assert.Equal(t, utils.BytesToMegabytes(349372416), g0.MemoryUsed)
+	assert.Equal(t, utils.BytesToMegabytes(4294967296), g0.MemoryTotal)
 	assert.Equal(t, 1.0, g0.Count)
 
 	g1, ok := gm.GpuDataMap["n1"]
@@ -275,8 +276,8 @@ func TestParseNvtopData(t *testing.T) {
 	assert.Equal(t, 48.0, g1.Temperature)
 	assert.Equal(t, 12.0, g1.Usage)
 	assert.Equal(t, 9.0, g1.Power)
-	assert.Equal(t, bytesToMegabytes(1213784064), g1.MemoryUsed)
-	assert.Equal(t, bytesToMegabytes(16929173504), g1.MemoryTotal)
+	assert.Equal(t, utils.BytesToMegabytes(1213784064), g1.MemoryUsed)
+	assert.Equal(t, utils.BytesToMegabytes(16929173504), g1.MemoryTotal)
 	assert.Equal(t, 1.0, g1.Count)
 }
 

agent/mdraid_linux.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/smart"
 )
 
@@ -16,7 +17,6 @@ import (
 var mdraidSysfsRoot = "/sys"
 
 type mdraidHealth struct {
-	name          string
 	level         string
 	arrayState    string
 	degraded      uint64
@@ -28,6 +28,7 @@ type mdraidHealth struct {
 	capacity      uint64
 }
 
+// scanMdraidDevices discovers Linux md arrays exposed in sysfs.
 func scanMdraidDevices() []*DeviceInfo {
 	blockDir := filepath.Join(mdraidSysfsRoot, "block")
 	entries, err := os.ReadDir(blockDir)
@@ -42,7 +43,7 @@ func scanMdraidDevices() []*DeviceInfo {
 			continue
 		}
 		mdDir := filepath.Join(blockDir, name, "md")
-		if !fileExists(filepath.Join(mdDir, "array_state")) {
+		if !utils.FileExists(filepath.Join(mdDir, "array_state")) {
 			continue
 		}
 
@@ -58,6 +59,7 @@ func scanMdraidDevices() []*DeviceInfo {
 	return devices
 }
 
+// collectMdraidHealth reads mdraid health and stores it in SmartDataMap.
 func (sm *SmartManager) collectMdraidHealth(deviceInfo *DeviceInfo) (bool, error) {
 	if deviceInfo == nil || deviceInfo.Name == "" {
 		return false, nil
@@ -115,19 +117,16 @@ func (sm *SmartManager) collectMdraidHealth(deviceInfo *DeviceInfo) (bool, error
 	if health.level != "" {
 		data.ModelName = "Linux MD RAID (" + health.level + ")"
 	}
-	data.SerialNumber = ""
-	data.FirmwareVersion = ""
 	data.Capacity = health.capacity
-	data.Temperature = 0
 	data.SmartStatus = status
 	data.DiskName = filepath.Join("/dev", base)
 	data.DiskType = "mdraid"
 	data.Attributes = attrs
-	sm.SmartDataMap[key] = data
 
 	return true, nil
 }
 
+// readMdraidHealth reads md array health fields from sysfs.
 func readMdraidHealth(blockName string) (mdraidHealth, bool) {
 	var out mdraidHealth
 
@@ -136,25 +135,24 @@ func readMdraidHealth(blockName string) (mdraidHealth, bool) {
 	}
 
 	mdDir := filepath.Join(mdraidSysfsRoot, "block", blockName, "md")
-	arrayState, okState := readStringFileOK(filepath.Join(mdDir, "array_state"))
+	arrayState, okState := utils.ReadStringFileOK(filepath.Join(mdDir, "array_state"))
 	if !okState {
 		return out, false
 	}
 
-	out.name = blockName
 	out.arrayState = arrayState
-	out.level = readStringFile(filepath.Join(mdDir, "level"))
-	out.syncAction = readStringFile(filepath.Join(mdDir, "sync_action"))
-	out.syncCompleted = readStringFile(filepath.Join(mdDir, "sync_completed"))
-	out.syncSpeed = readStringFile(filepath.Join(mdDir, "sync_speed"))
+	out.level = utils.ReadStringFile(filepath.Join(mdDir, "level"))
+	out.syncAction = utils.ReadStringFile(filepath.Join(mdDir, "sync_action"))
+	out.syncCompleted = utils.ReadStringFile(filepath.Join(mdDir, "sync_completed"))
+	out.syncSpeed = utils.ReadStringFile(filepath.Join(mdDir, "sync_speed"))
 
-	if val, ok := readUintFile(filepath.Join(mdDir, "raid_disks")); ok {
+	if val, ok := utils.ReadUintFile(filepath.Join(mdDir, "raid_disks")); ok {
 		out.raidDisks = val
 	}
-	if val, ok := readUintFile(filepath.Join(mdDir, "degraded")); ok {
+	if val, ok := utils.ReadUintFile(filepath.Join(mdDir, "degraded")); ok {
 		out.degraded = val
 	}
-	if val, ok := readUintFile(filepath.Join(mdDir, "mismatch_cnt")); ok {
+	if val, ok := utils.ReadUintFile(filepath.Join(mdDir, "mismatch_cnt")); ok {
 		out.mismatchCnt = val
 	}
 
@@ -165,6 +163,7 @@ func readMdraidHealth(blockName string) (mdraidHealth, bool) {
 	return out, true
 }
 
+// mdraidSmartStatus maps md state/sync signals to a SMART-like status.
 func mdraidSmartStatus(health mdraidHealth) string {
 	state := strings.ToLower(strings.TrimSpace(health.arrayState))
 	switch state {
@@ -174,18 +173,18 @@ func mdraidSmartStatus(health mdraidHealth) string {
 	if health.degraded > 0 {
 		return "FAILED"
 	}
-
 	switch strings.ToLower(strings.TrimSpace(health.syncAction)) {
 	case "resync", "recover", "reshape", "check", "repair":
 		return "WARNING"
 	}
-
-	if state == "clean" || state == "active" || state == "readonly" {
+	switch state {
+	case "clean", "active", "active-idle", "write-pending", "read-auto", "readonly":
 		return "PASSED"
 	}
 	return "UNKNOWN"
 }
 
+// isMdraidBlockName matches /dev/mdN-style block device names.
 func isMdraidBlockName(name string) bool {
 	if !strings.HasPrefix(name, "md") {
 		return false
@@ -202,35 +201,23 @@ func isMdraidBlockName(name string) bool {
 	return true
 }
 
-func readUintFile(path string) (uint64, bool) {
-	raw, ok := readStringFileOK(path)
-	if !ok {
-		return 0, false
-	}
-	parsed, err := strconv.ParseUint(strings.TrimSpace(raw), 10, 64)
-	if err != nil {
-		return 0, false
-	}
-	return parsed, true
-}
-
+// readMdraidBlockCapacityBytes converts block size metadata into bytes.
 func readMdraidBlockCapacityBytes(blockName, root string) (uint64, bool) {
 	sizePath := filepath.Join(root, "block", blockName, "size")
 	lbsPath := filepath.Join(root, "block", blockName, "queue", "logical_block_size")
 
-	sizeStr, ok := readStringFileOK(sizePath)
+	sizeStr, ok := utils.ReadStringFileOK(sizePath)
 	if !ok {
 		return 0, false
 	}
-	sectors, err := strconv.ParseUint(strings.TrimSpace(sizeStr), 10, 64)
+	sectors, err := strconv.ParseUint(sizeStr, 10, 64)
 	if err != nil || sectors == 0 {
 		return 0, false
 	}
 
-	lbsStr, ok := readStringFileOK(lbsPath)
 	logicalBlockSize := uint64(512)
-	if ok {
-		if parsed, err := strconv.ParseUint(strings.TrimSpace(lbsStr), 10, 64); err == nil && parsed > 0 {
+	if lbsStr, ok := utils.ReadStringFileOK(lbsPath); ok {
+		if parsed, err := strconv.ParseUint(lbsStr, 10, 64); err == nil && parsed > 0 {
 			logicalBlockSize = parsed
 		}
 	}

agent/network.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel/agent/deltatracker"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 	psutilNet "github.com/shirou/gopsutil/v4/net"
 )
@@ -94,7 +95,7 @@ func (a *Agent) initializeNetIoStats() {
 	a.netInterfaces = make(map[string]struct{}, 0)
 
 	// parse NICS env var for whitelist / blacklist
-	nicsEnvVal, nicsEnvExists := GetEnv("NICS")
+	nicsEnvVal, nicsEnvExists := utils.GetEnv("NICS")
 	var nicCfg *NicConfig
 	if nicsEnvExists {
 		nicCfg = newNicConfig(nicsEnvVal)
@@ -215,8 +216,8 @@ func (a *Agent) applyNetworkTotals(
 	totalBytesSent, totalBytesRecv uint64,
 	bytesSentPerSecond, bytesRecvPerSecond uint64,
 ) {
-	networkSentPs := bytesToMegabytes(float64(bytesSentPerSecond))
-	networkRecvPs := bytesToMegabytes(float64(bytesRecvPerSecond))
+	networkSentPs := utils.BytesToMegabytes(float64(bytesSentPerSecond))
+	networkRecvPs := utils.BytesToMegabytes(float64(bytesRecvPerSecond))
 	if networkSentPs > 10_000 || networkRecvPs > 10_000 {
 		slog.Warn("Invalid net stats. Resetting.", "sent", networkSentPs, "recv", networkRecvPs)
 		for _, v := range netIO {

agent/sensors.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"unicode/utf8"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/system"
 
 	"github.com/shirou/gopsutil/v4/common"
@@ -26,9 +27,9 @@ type SensorConfig struct {
 }
 
 func (a *Agent) newSensorConfig() *SensorConfig {
-	primarySensor, _ := GetEnv("PRIMARY_SENSOR")
-	sysSensors, _ := GetEnv("SYS_SENSORS")
-	sensorsEnvVal, sensorsSet := GetEnv("SENSORS")
+	primarySensor, _ := utils.GetEnv("PRIMARY_SENSOR")
+	sysSensors, _ := utils.GetEnv("SYS_SENSORS")
+	sensorsEnvVal, sensorsSet := utils.GetEnv("SENSORS")
 	skipCollection := sensorsSet && sensorsEnvVal == ""
 
 	return a.newSensorConfigWithEnv(primarySensor, sysSensors, sensorsEnvVal, skipCollection)
@@ -135,7 +136,7 @@ func (a *Agent) updateTemperatures(systemStats *system.Stats) {
 		case sensorName:
 			a.systemInfo.DashboardTemp = sensor.Temperature
 		}
-		systemStats.Temperatures[sensorName] = twoDecimals(sensor.Temperature)
+		systemStats.Temperatures[sensorName] = utils.TwoDecimals(sensor.Temperature)
 	}
 }
 

agent/server.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/common"
 	"github.com/henrygd/beszel/internal/entities/system"
 
@@ -36,7 +37,7 @@ var hubVersions map[string]semver.Version
 // and begins listening for connections. Returns an error if the server
 // is already running or if there's an issue starting the server.
 func (a *Agent) StartServer(opts ServerOptions) error {
-	if disableSSH, _ := GetEnv("DISABLE_SSH"); disableSSH == "true" {
+	if disableSSH, _ := utils.GetEnv("DISABLE_SSH"); disableSSH == "true" {
 		return errors.New("SSH disabled")
 	}
 	if a.server != nil {
@@ -238,11 +239,11 @@ func ParseKeys(input string) ([]gossh.PublicKey, error) {
 // and finally defaults to ":45876".
 func GetAddress(addr string) string {
 	if addr == "" {
-		addr, _ = GetEnv("LISTEN")
+		addr, _ = utils.GetEnv("LISTEN")
 	}
 	if addr == "" {
 		// Legacy PORT environment variable support
-		addr, _ = GetEnv("PORT")
+		addr, _ = utils.GetEnv("PORT")
 	}
 	if addr == "" {
 		return ":45876"
@@ -258,7 +259,7 @@ func GetAddress(addr string) string {
 // It checks the NETWORK environment variable first, then infers from
 // the address format: addresses starting with "/" are "unix", others are "tcp".
 func GetNetwork(addr string) string {
-	if network, ok := GetEnv("NETWORK"); ok && network != "" {
+	if network, ok := utils.GetEnv("NETWORK"); ok && network != "" {
 		return network
 	}
 	if strings.HasPrefix(addr, "/") {

agent/smart.go

@@ -18,6 +18,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/smart"
 )
 
@@ -156,7 +157,7 @@ func (sm *SmartManager) ScanDevices(force bool) error {
 	currentDevices := sm.devicesSnapshot()
 
 	var configuredDevices []*DeviceInfo
-	if configuredRaw, ok := GetEnv("SMART_DEVICES"); ok {
+	if configuredRaw, ok := utils.GetEnv("SMART_DEVICES"); ok {
 		slog.Info("SMART_DEVICES", "value", configuredRaw)
 		config := strings.TrimSpace(configuredRaw)
 		if config == "" {
@@ -222,7 +223,7 @@ func (sm *SmartManager) ScanDevices(force bool) error {
 }
 
 func (sm *SmartManager) parseConfiguredDevices(config string) ([]*DeviceInfo, error) {
-	splitChar := os.Getenv("SMART_DEVICES_SEPARATOR")
+	splitChar, _ := utils.GetEnv("SMART_DEVICES_SEPARATOR")
 	if splitChar == "" {
 		splitChar = ","
 	}
@@ -260,7 +261,7 @@ func (sm *SmartManager) parseConfiguredDevices(config string) ([]*DeviceInfo, er
 }
 
 func (sm *SmartManager) refreshExcludedDevices() {
-	rawValue, _ := GetEnv("EXCLUDE_SMART")
+	rawValue, _ := utils.GetEnv("EXCLUDE_SMART")
 	sm.excludedDevices = make(map[string]struct{})
 
 	for entry := range strings.SplitSeq(rawValue, ",") {
@@ -870,15 +871,18 @@ func (sm *SmartManager) parseSmartForSata(output []byte) (bool, int) {
 	smartData.FirmwareVersion = data.FirmwareVersion
 	smartData.Capacity = data.UserCapacity.Bytes
 	smartData.Temperature = data.Temperature.Current
-	if smartData.Temperature == 0 {
-		if temp, ok := temperatureFromAtaDeviceStatistics(data.AtaDeviceStatistics); ok {
-			smartData.Temperature = temp
-		}
-	}
 	smartData.SmartStatus = getSmartStatus(smartData.Temperature, data.SmartStatus.Passed)
 	smartData.DiskName = data.Device.Name
 	smartData.DiskType = data.Device.Type
 
+	// get values from ata_device_statistics if necessary
+	var ataDeviceStats smart.AtaDeviceStatistics
+	if smartData.Temperature == 0 {
+		if temp := findAtaDeviceStatisticsValue(&data, &ataDeviceStats, 5, "Current Temperature", 0, 255); temp != nil {
+			smartData.Temperature = uint8(*temp)
+		}
+	}
+
 	// update SmartAttributes
 	smartData.Attributes = make([]*smart.SmartAttribute, 0, len(data.AtaSmartAttributes.Table))
 	for _, attr := range data.AtaSmartAttributes.Table {
@@ -913,23 +917,20 @@ func getSmartStatus(temperature uint8, passed bool) string {
 	}
 }
 
-func temperatureFromAtaDeviceStatistics(stats smart.AtaDeviceStatistics) (uint8, bool) {
-	entry := findAtaDeviceStatisticsEntry(stats, 5, "Current Temperature")
-	if entry == nil || entry.Value == nil {
-		return 0, false
-	}
-	if *entry.Value > 255 {
-		return 0, false
-	}
-	return uint8(*entry.Value), true
-}
-
 // findAtaDeviceStatisticsEntry centralizes ATA devstat lookups so additional
 // metrics can be pulled from the same structure in the future.
-func findAtaDeviceStatisticsEntry(stats smart.AtaDeviceStatistics, pageNumber uint8, entryName string) *smart.AtaDeviceStatisticsEntry {
-	for pageIdx := range stats.Pages {
-		page := &stats.Pages[pageIdx]
-		if page.Number != pageNumber {
+func findAtaDeviceStatisticsValue(data *smart.SmartInfoForSata, ataDeviceStats *smart.AtaDeviceStatistics, entryNumber uint8, entryName string, minValue, maxValue int64) *int64 {
+	if len(ataDeviceStats.Pages) == 0 {
+		if len(data.AtaDeviceStatistics) == 0 {
+			return nil
+		}
+		if err := json.Unmarshal(data.AtaDeviceStatistics, ataDeviceStats); err != nil {
+			return nil
+		}
+	}
+	for pageIdx := range ataDeviceStats.Pages {
+		page := &ataDeviceStats.Pages[pageIdx]
+		if page.Number != entryNumber {
 			continue
 		}
 		for entryIdx := range page.Table {
@@ -937,7 +938,10 @@ func findAtaDeviceStatisticsEntry(stats smart.AtaDeviceStatistics, pageNumber ui
 			if !strings.EqualFold(entry.Name, entryName) {
 				continue
 			}
-			return entry
+			if entry.Value == nil || *entry.Value < minValue || *entry.Value > maxValue {
+				return nil
+			}
+			return entry.Value
 		}
 	}
 	return nil

agent/smart_test.go

@@ -121,6 +121,78 @@ func TestParseSmartForSataDeviceStatisticsTemperature(t *testing.T) {
 	assert.Equal(t, uint8(22), deviceData.Temperature)
 }
 
+func TestParseSmartForSataAtaDeviceStatistics(t *testing.T) {
+	// tests that ata_device_statistics values are parsed correctly
+	jsonPayload := []byte(`{
+		"smartctl": {"exit_status": 0},
+		"device": {"name": "/dev/sdb", "type": "sat"},
+		"model_name": "SanDisk SSD U110 16GB",
+		"serial_number": "lksjfh23lhj",
+		"firmware_version": "U21B001",
+		"user_capacity": {"bytes": 16013942784},
+		"smart_status": {"passed": true},
+		"ata_smart_attributes": {"table": []},
+		"ata_device_statistics": {
+			"pages": [
+				{
+					"number": 5,
+					"name": "Temperature Statistics",
+					"table": [
+						{"name": "Current Temperature", "value": 43, "flags": {"valid": true}},
+						{"name": "Specified Minimum Operating Temperature", "value": -20, "flags": {"valid": true}}
+					]
+				}
+			]
+		}
+	}`)
+
+	sm := &SmartManager{SmartDataMap: make(map[string]*smart.SmartData)}
+	hasData, exitStatus := sm.parseSmartForSata(jsonPayload)
+	require.True(t, hasData)
+	assert.Equal(t, 0, exitStatus)
+
+	deviceData, ok := sm.SmartDataMap["lksjfh23lhj"]
+	require.True(t, ok, "expected smart data entry for serial lksjfh23lhj")
+	assert.Equal(t, uint8(43), deviceData.Temperature)
+}
+
+func TestParseSmartForSataNegativeDeviceStatistics(t *testing.T) {
+	// Tests that negative values in ata_device_statistics (e.g. min operating temp)
+	// do not cause the entire SAT parser to fail.
+	jsonPayload := []byte(`{
+		"smartctl": {"exit_status": 0},
+		"device": {"name": "/dev/sdb", "type": "sat"},
+		"model_name": "SanDisk SSD U110 16GB",
+		"serial_number": "NEGATIVE123",
+		"firmware_version": "U21B001",
+		"user_capacity": {"bytes": 16013942784},
+		"smart_status": {"passed": true},
+		"temperature": {"current": 38},
+		"ata_smart_attributes": {"table": []},
+		"ata_device_statistics": {
+			"pages": [
+				{
+					"number": 5,
+					"name": "Temperature Statistics",
+					"table": [
+						{"name": "Current Temperature", "value": 38, "flags": {"valid": true}},
+						{"name": "Specified Minimum Operating Temperature", "value": -20, "flags": {"valid": true}}
+					]
+				}
+			]
+		}
+	}`)
+
+	sm := &SmartManager{SmartDataMap: make(map[string]*smart.SmartData)}
+	hasData, exitStatus := sm.parseSmartForSata(jsonPayload)
+	require.True(t, hasData)
+	assert.Equal(t, 0, exitStatus)
+
+	deviceData, ok := sm.SmartDataMap["NEGATIVE123"]
+	require.True(t, ok, "expected smart data entry for serial NEGATIVE123")
+	assert.Equal(t, uint8(38), deviceData.Temperature)
+}
+
 func TestParseSmartForSataParentheticalRawValue(t *testing.T) {
 	jsonPayload := []byte(`{
 		"smartctl": {"exit_status": 0},
@@ -727,6 +799,182 @@ func TestIsVirtualDeviceScsi(t *testing.T) {
 	}
 }
 
+func TestFindAtaDeviceStatisticsValue(t *testing.T) {
+	val42 := int64(42)
+	val100 := int64(100)
+	valMinus20 := int64(-20)
+
+	tests := []struct {
+		name           string
+		data           smart.SmartInfoForSata
+		ataDeviceStats smart.AtaDeviceStatistics
+		entryNumber    uint8
+		entryName      string
+		minValue       int64
+		maxValue       int64
+		expectedValue  *int64
+	}{
+		{
+			name: "value in ataDeviceStats",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Current Temperature", Value: &val42},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: &val42,
+		},
+		{
+			name: "value unmarshaled from data",
+			data: smart.SmartInfoForSata{
+				AtaDeviceStatistics: []byte(`{"pages":[{"number":5,"table":[{"name":"Current Temperature","value":100}]}]}`),
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      255,
+			expectedValue: &val100,
+		},
+		{
+			name: "value out of range (too high)",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Current Temperature", Value: &val100},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      50,
+			expectedValue: nil,
+		},
+		{
+			name: "value out of range (too low)",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Min Temp", Value: &valMinus20},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Min Temp",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: nil,
+		},
+		{
+			name:          "no statistics available",
+			data:          smart.SmartInfoForSata{},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      255,
+			expectedValue: nil,
+		},
+		{
+			name: "wrong page number",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 1,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Current Temperature", Value: &val42},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: nil,
+		},
+		{
+			name: "wrong entry name",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Other Stat", Value: &val42},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: nil,
+		},
+		{
+			name: "case insensitive name match",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "CURRENT TEMPERATURE", Value: &val42},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: &val42,
+		},
+		{
+			name: "entry value is nil",
+			ataDeviceStats: smart.AtaDeviceStatistics{
+				Pages: []smart.AtaDeviceStatisticsPage{
+					{
+						Number: 5,
+						Table: []smart.AtaDeviceStatisticsEntry{
+							{Name: "Current Temperature", Value: nil},
+						},
+					},
+				},
+			},
+			entryNumber:   5,
+			entryName:     "Current Temperature",
+			minValue:      0,
+			maxValue:      100,
+			expectedValue: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := findAtaDeviceStatisticsValue(&tt.data, &tt.ataDeviceStats, tt.entryNumber, tt.entryName, tt.minValue, tt.maxValue)
+			if tt.expectedValue == nil {
+				assert.Nil(t, result)
+			} else {
+				require.NotNil(t, result)
+				assert.Equal(t, *tt.expectedValue, *result)
+			}
+		})
+	}
+}
+
 func TestRefreshExcludedDevices(t *testing.T) {
 	tests := []struct {
 		name         string

agent/system.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/henrygd/beszel"
 	"github.com/henrygd/beszel/agent/battery"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/agent/zfs"
 	"github.com/henrygd/beszel/internal/entities/container"
 	"github.com/henrygd/beszel/internal/entities/system"
@@ -127,13 +128,13 @@ func (a *Agent) getSystemStats(cacheTimeMs uint16) system.Stats {
 	// cpu metrics
 	cpuMetrics, err := getCpuMetrics(cacheTimeMs)
 	if err == nil {
-		systemStats.Cpu = twoDecimals(cpuMetrics.Total)
+		systemStats.Cpu = utils.TwoDecimals(cpuMetrics.Total)
 		systemStats.CpuBreakdown = []float64{
-			twoDecimals(cpuMetrics.User),
-			twoDecimals(cpuMetrics.System),
-			twoDecimals(cpuMetrics.Iowait),
-			twoDecimals(cpuMetrics.Steal),
-			twoDecimals(cpuMetrics.Idle),
+			utils.TwoDecimals(cpuMetrics.User),
+			utils.TwoDecimals(cpuMetrics.System),
+			utils.TwoDecimals(cpuMetrics.Iowait),
+			utils.TwoDecimals(cpuMetrics.Steal),
+			utils.TwoDecimals(cpuMetrics.Idle),
 		}
 	} else {
 		slog.Error("Error getting cpu metrics", "err", err)
@@ -157,8 +158,8 @@ func (a *Agent) getSystemStats(cacheTimeMs uint16) system.Stats {
 	// memory
 	if v, err := mem.VirtualMemory(); err == nil {
 		// swap
-		systemStats.Swap = bytesToGigabytes(v.SwapTotal)
-		systemStats.SwapUsed = bytesToGigabytes(v.SwapTotal - v.SwapFree - v.SwapCached)
+		systemStats.Swap = utils.BytesToGigabytes(v.SwapTotal)
+		systemStats.SwapUsed = utils.BytesToGigabytes(v.SwapTotal - v.SwapFree - v.SwapCached)
 		// cache + buffers value for default mem calculation
 		// note: gopsutil automatically adds SReclaimable to v.Cached
 		cacheBuff := v.Cached + v.Buffers - v.Shared
@@ -181,13 +182,13 @@ func (a *Agent) getSystemStats(cacheTimeMs uint16) system.Stats {
 			if arcSize, _ := zfs.ARCSize(); arcSize > 0 && arcSize < v.Used {
 				v.Used = v.Used - arcSize
 				v.UsedPercent = float64(v.Used) / float64(v.Total) * 100.0
-				systemStats.MemZfsArc = bytesToGigabytes(arcSize)
+				systemStats.MemZfsArc = utils.BytesToGigabytes(arcSize)
 			}
 		}
-		systemStats.Mem = bytesToGigabytes(v.Total)
-		systemStats.MemBuffCache = bytesToGigabytes(cacheBuff)
-		systemStats.MemUsed = bytesToGigabytes(v.Used)
-		systemStats.MemPct = twoDecimals(v.UsedPercent)
+		systemStats.Mem = utils.BytesToGigabytes(v.Total)
+		systemStats.MemBuffCache = utils.BytesToGigabytes(cacheBuff)
+		systemStats.MemUsed = utils.BytesToGigabytes(v.Used)
+		systemStats.MemPct = utils.TwoDecimals(v.UsedPercent)
 	}
 
 	// disk usage

agent/systemd.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/coreos/go-systemd/v22/dbus"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/henrygd/beszel/internal/entities/systemd"
 )
 
@@ -49,7 +50,7 @@ func isSystemdAvailable() bool {
 
 // newSystemdManager creates a new systemdManager.
 func newSystemdManager() (*systemdManager, error) {
-	if skipSystemd, _ := GetEnv("SKIP_SYSTEMD"); skipSystemd == "true" {
+	if skipSystemd, _ := utils.GetEnv("SKIP_SYSTEMD"); skipSystemd == "true" {
 		return nil, nil
 	}
 
@@ -294,7 +295,7 @@ func unescapeServiceName(name string) string {
 // otherwise defaults to "*service".
 func getServicePatterns() []string {
 	patterns := []string{}
-	if envPatterns, _ := GetEnv("SERVICE_PATTERNS"); envPatterns != "" {
+	if envPatterns, _ := utils.GetEnv("SERVICE_PATTERNS"); envPatterns != "" {
 		for pattern := range strings.SplitSeq(envPatterns, ",") {
 			pattern = strings.TrimSpace(pattern)
 			if pattern == "" {

agent/utils.go

@@ -1,15 +0,0 @@
-package agent
-
-import "math"
-
-func bytesToMegabytes(b float64) float64 {
-	return twoDecimals(b / 1048576)
-}
-
-func bytesToGigabytes(b uint64) float64 {
-	return twoDecimals(float64(b) / 1073741824)
-}
-
-func twoDecimals(value float64) float64 {
-	return math.Round(value*100) / 100
-}

agent/utils/utils.go

@@ -0,0 +1,70 @@
+package utils
+
+import (
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// GetEnv retrieves an environment variable with a "BESZEL_AGENT_" prefix, or falls back to the unprefixed key.
+func GetEnv(key string) (value string, exists bool) {
+	if value, exists = os.LookupEnv("BESZEL_AGENT_" + key); exists {
+		return value, exists
+	}
+	return os.LookupEnv(key)
+}
+
+// BytesToMegabytes converts bytes to megabytes and rounds to two decimal places.
+func BytesToMegabytes(b float64) float64 {
+	return TwoDecimals(b / 1048576)
+}
+
+// BytesToGigabytes converts bytes to gigabytes and rounds to two decimal places.
+func BytesToGigabytes(b uint64) float64 {
+	return TwoDecimals(float64(b) / 1073741824)
+}
+
+// TwoDecimals rounds a float64 value to two decimal places.
+func TwoDecimals(value float64) float64 {
+	return math.Round(value*100) / 100
+}
+
+// func RoundFloat(val float64, precision uint) float64 {
+//     ratio := math.Pow(10, float64(precision))
+//     return math.Round(val*ratio) / ratio
+// }
+
+// ReadStringFile returns trimmed file contents or empty string on error.
+func ReadStringFile(path string) string {
+	content, _ := ReadStringFileOK(path)
+	return content
+}
+
+// ReadStringFileOK returns trimmed file contents and read success.
+func ReadStringFileOK(path string) (string, bool) {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return "", false
+	}
+	return strings.TrimSpace(string(b)), true
+}
+
+// FileExists reports whether the given path exists.
+func FileExists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// ReadUintFile parses a decimal uint64 value from a file.
+func ReadUintFile(path string) (uint64, bool) {
+	raw, ok := ReadStringFileOK(path)
+	if !ok {
+		return 0, false
+	}
+	parsed, err := strconv.ParseUint(raw, 10, 64)
+	if err != nil {
+		return 0, false
+	}
+	return parsed, true
+}

agent/utils/utils_test.go

@@ -0,0 +1,165 @@
+package utils
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTwoDecimals(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    float64
+		expected float64
+	}{
+		{"round down", 1.234, 1.23},
+		{"round half up", 1.235, 1.24}, // math.Round rounds half up
+		{"no rounding needed", 1.23, 1.23},
+		{"negative number", -1.235, -1.24}, // math.Round rounds half up (more negative)
+		{"zero", 0.0, 0.0},
+		{"large number", 123.456, 123.46}, // rounds 5 up
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := TwoDecimals(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestBytesToMegabytes(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    float64
+		expected float64
+	}{
+		{"1 MB", 1048576, 1.0},
+		{"512 KB", 524288, 0.5},
+		{"zero", 0, 0},
+		{"large value", 1073741824, 1024}, // 1 GB = 1024 MB
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := BytesToMegabytes(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestBytesToGigabytes(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    uint64
+		expected float64
+	}{
+		{"1 GB", 1073741824, 1.0},
+		{"512 MB", 536870912, 0.5},
+		{"0 GB", 0, 0},
+		{"2 GB", 2147483648, 2.0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := BytesToGigabytes(tt.input)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestFileFunctions(t *testing.T) {
+	tmpDir := t.TempDir()
+	testFilePath := filepath.Join(tmpDir, "test.txt")
+	testContent := "hello world"
+
+	// Test FileExists (false)
+	assert.False(t, FileExists(testFilePath))
+
+	// Test ReadStringFileOK (false)
+	content, ok := ReadStringFileOK(testFilePath)
+	assert.False(t, ok)
+	assert.Empty(t, content)
+
+	// Test ReadStringFile (empty)
+	assert.Empty(t, ReadStringFile(testFilePath))
+
+	// Write file
+	err := os.WriteFile(testFilePath, []byte(testContent+"\n "), 0644)
+	assert.NoError(t, err)
+
+	// Test FileExists (true)
+	assert.True(t, FileExists(testFilePath))
+
+	// Test ReadStringFileOK (true)
+	content, ok = ReadStringFileOK(testFilePath)
+	assert.True(t, ok)
+	assert.Equal(t, testContent, content)
+
+	// Test ReadStringFile (content)
+	assert.Equal(t, testContent, ReadStringFile(testFilePath))
+}
+
+func TestReadUintFile(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	t.Run("valid uint", func(t *testing.T) {
+		path := filepath.Join(tmpDir, "uint.txt")
+		os.WriteFile(path, []byte(" 12345\n"), 0644)
+		val, ok := ReadUintFile(path)
+		assert.True(t, ok)
+		assert.Equal(t, uint64(12345), val)
+	})
+
+	t.Run("invalid uint", func(t *testing.T) {
+		path := filepath.Join(tmpDir, "invalid.txt")
+		os.WriteFile(path, []byte("abc"), 0644)
+		val, ok := ReadUintFile(path)
+		assert.False(t, ok)
+		assert.Equal(t, uint64(0), val)
+	})
+
+	t.Run("missing file", func(t *testing.T) {
+		path := filepath.Join(tmpDir, "missing.txt")
+		val, ok := ReadUintFile(path)
+		assert.False(t, ok)
+		assert.Equal(t, uint64(0), val)
+	})
+}
+
+func TestGetEnv(t *testing.T) {
+	key := "TEST_VAR"
+	prefixedKey := "BESZEL_AGENT_" + key
+
+	t.Run("prefixed variable exists", func(t *testing.T) {
+		os.Setenv(prefixedKey, "prefixed_val")
+		os.Setenv(key, "unprefixed_val")
+		defer os.Unsetenv(prefixedKey)
+		defer os.Unsetenv(key)
+
+		val, exists := GetEnv(key)
+		assert.True(t, exists)
+		assert.Equal(t, "prefixed_val", val)
+	})
+
+	t.Run("only unprefixed variable exists", func(t *testing.T) {
+		os.Unsetenv(prefixedKey)
+		os.Setenv(key, "unprefixed_val")
+		defer os.Unsetenv(key)
+
+		val, exists := GetEnv(key)
+		assert.True(t, exists)
+		assert.Equal(t, "unprefixed_val", val)
+	})
+
+	t.Run("neither variable exists", func(t *testing.T) {
+		os.Unsetenv(prefixedKey)
+		os.Unsetenv(key)
+
+		val, exists := GetEnv(key)
+		assert.False(t, exists)
+		assert.Empty(t, val)
+	})
+}

internal/cmd/agent/agent.go

@@ -9,6 +9,7 @@ import (
 	"github.com/henrygd/beszel"
 	"github.com/henrygd/beszel/agent"
 	"github.com/henrygd/beszel/agent/health"
+	"github.com/henrygd/beszel/agent/utils"
 	"github.com/spf13/pflag"
 	"golang.org/x/crypto/ssh"
 )
@@ -116,12 +117,12 @@ func (opts *cmdOptions) loadPublicKeys() ([]ssh.PublicKey, error) {
 	}
 
 	// Try environment variable
-	if key, ok := agent.GetEnv("KEY"); ok && key != "" {
+	if key, ok := utils.GetEnv("KEY"); ok && key != "" {
 		return agent.ParseKeys(key)
 	}
 
 	// Try key file
-	keyFile, ok := agent.GetEnv("KEY_FILE")
+	keyFile, ok := utils.GetEnv("KEY_FILE")
 	if !ok {
 		return nil, fmt.Errorf("no key provided: must set -key flag, KEY env var, or KEY_FILE env var. Use 'beszel-agent help' for usage")
 	}

internal/entities/smart/smart.go

@@ -143,8 +143,8 @@ type AtaDeviceStatisticsPage struct {
 }
 
 type AtaDeviceStatisticsEntry struct {
-	Name  string  `json:"name"`
-	Value *uint64 `json:"value,omitempty"`
+	Name  string `json:"name"`
+	Value *int64 `json:"value,omitempty"`
 }
 
 type AtaSmartAttribute struct {
@@ -356,8 +356,8 @@ type SmartInfoForSata struct {
 	SmartStatus SmartStatusInfo `json:"smart_status"`
 	// AtaSmartData                 AtaSmartData                 `json:"ata_smart_data"`
 	// AtaSctCapabilities           AtaSctCapabilities           `json:"ata_sct_capabilities"`
-	AtaSmartAttributes  AtaSmartAttributes  `json:"ata_smart_attributes"`
-	AtaDeviceStatistics AtaDeviceStatistics `json:"ata_device_statistics"`
+	AtaSmartAttributes  AtaSmartAttributes `json:"ata_smart_attributes"`
+	AtaDeviceStatistics json.RawMessage    `json:"ata_device_statistics"`
 	// PowerOnTime                  PowerOnTimeInfo              `json:"power_on_time"`
 	// PowerCycleCount              uint16                       `json:"power_cycle_count"`
 	Temperature TemperatureInfo `json:"temperature"`

internal/hub/agent_connect_test.go

@@ -917,7 +917,7 @@ func TestAgentWebSocketIntegration(t *testing.T) {
 
 			// Wait for connection result
 			maxWait := 2 * time.Second
-			time.Sleep(20 * time.Millisecond)
+			time.Sleep(40 * time.Millisecond)
 			checkInterval := 20 * time.Millisecond
 			timeout := time.After(maxWait)
 			ticker := time.Tick(checkInterval)

internal/hub/expirymap/expirymap.go

@@ -1,29 +1,33 @@
+// Package expirymap provides a thread-safe map with expiring entries.
+// It supports TTL-based expiration with both lazy cleanup on access
+// and periodic background cleanup.
 package expirymap
 
 import (
-	"reflect"
+	"sync"
 	"time"
 
 	"github.com/pocketbase/pocketbase/tools/store"
 )
 
-type val[T any] struct {
+type val[T comparable] struct {
 	value   T
 	expires time.Time
 }
 
-type ExpiryMap[T any] struct {
-	store           *store.Store[string, *val[T]]
-	cleanupInterval time.Duration
+type ExpiryMap[T comparable] struct {
+	store    *store.Store[string, *val[T]]
+	stopChan chan struct{}
+	stopOnce sync.Once
 }
 
 // New creates a new expiry map with custom cleanup interval
-func New[T any](cleanupInterval time.Duration) *ExpiryMap[T] {
+func New[T comparable](cleanupInterval time.Duration) *ExpiryMap[T] {
 	m := &ExpiryMap[T]{
-		store:           store.New(map[string]*val[T]{}),
-		cleanupInterval: cleanupInterval,
+		store:    store.New(map[string]*val[T]{}),
+		stopChan: make(chan struct{}),
 	}
-	m.startCleaner()
+	go m.startCleaner(cleanupInterval)
 	return m
 }
 
@@ -55,7 +59,7 @@ func (m *ExpiryMap[T]) GetOk(key string) (T, bool) {
 // GetByValue retrieves a value by value
 func (m *ExpiryMap[T]) GetByValue(val T) (key string, value T, ok bool) {
 	for key, v := range m.store.GetAll() {
-		if reflect.DeepEqual(v.value, val) {
+		if v.value == val {
 			// check if expired
 			if v.expires.Before(time.Now()) {
 				m.store.Remove(key)
@@ -75,7 +79,7 @@ func (m *ExpiryMap[T]) Remove(key string) {
 // RemovebyValue removes a value by value
 func (m *ExpiryMap[T]) RemovebyValue(value T) (T, bool) {
 	for key, val := range m.store.GetAll() {
-		if reflect.DeepEqual(val.value, value) {
+		if val.value == value {
 			m.store.Remove(key)
 			return val.value, true
 		}
@@ -84,13 +88,23 @@ func (m *ExpiryMap[T]) RemovebyValue(value T) (T, bool) {
 }
 
 // startCleaner runs the background cleanup process
-func (m *ExpiryMap[T]) startCleaner() {
-	go func() {
-		tick := time.Tick(m.cleanupInterval)
-		for range tick {
+func (m *ExpiryMap[T]) startCleaner(interval time.Duration) {
+	tick := time.Tick(interval)
+	for {
+		select {
+		case <-tick:
 			m.cleanup()
+		case <-m.stopChan:
+			return
 		}
-	}()
+	}
+}
+
+// StopCleaner stops the background cleanup process
+func (m *ExpiryMap[T]) StopCleaner() {
+	m.stopOnce.Do(func() {
+		close(m.stopChan)
+	})
 }
 
 // cleanup removes all expired entries

internal/hub/expirymap/expirymap_test.go

@@ -4,6 +4,7 @@ package expirymap
 
 import (
 	"testing"
+	"testing/synctest"
 	"time"
 
 	"github.com/stretchr/testify/assert"
@@ -473,3 +474,52 @@ func TestExpiryMap_ValueOperations_Integration(t *testing.T) {
 	assert.Equal(t, "unique", value)
 	assert.Equal(t, "key2", key)
 }
+
+func TestExpiryMap_Cleaner(t *testing.T) {
+	synctest.Test(t, func(t *testing.T) {
+		em := New[string](time.Second)
+		defer em.StopCleaner()
+
+		em.Set("test", "value", 500*time.Millisecond)
+
+		// Wait 600ms, value is expired but cleaner hasn't run yet (interval is 1s)
+		time.Sleep(600 * time.Millisecond)
+		synctest.Wait()
+
+		// Map should still hold the value in its internal store before lazy access or cleaner
+		assert.Equal(t, 1, len(em.store.GetAll()), "store should still have 1 item before cleaner runs")
+
+		// Wait another 500ms so cleaner (1s interval) runs
+		time.Sleep(500 * time.Millisecond)
+		synctest.Wait() // Wait for background goroutine to process the tick
+
+		assert.Equal(t, 0, len(em.store.GetAll()), "store should be empty after cleaner runs")
+	})
+}
+
+func TestExpiryMap_StopCleaner(t *testing.T) {
+	em := New[string](time.Hour)
+
+	// Initially, stopChan is open, reading would block
+	select {
+	case <-em.stopChan:
+		t.Fatal("stopChan should be open initially")
+	default:
+		// success
+	}
+
+	em.StopCleaner()
+
+	// After StopCleaner, stopChan is closed, reading returns immediately
+	select {
+	case <-em.stopChan:
+		// success
+	default:
+		t.Fatal("stopChan was not closed by StopCleaner")
+	}
+
+	// Calling StopCleaner again should NOT panic thanks to sync.Once
+	assert.NotPanics(t, func() {
+		em.StopCleaner()
+	})
+}

internal/hub/systems/system.go

@@ -48,7 +48,6 @@ type System struct {
 	detailsFetched atomic.Bool             // True if static system details have been fetched and saved
 	smartFetching  atomic.Bool             // True if SMART devices are currently being fetched
 	smartInterval  time.Duration           // Interval for periodic SMART data updates
-	lastSmartFetch atomic.Int64            // Unix milliseconds of last SMART data fetch
 }
 
 func (sm *SystemManager) NewSystem(systemId string) *System {
@@ -142,11 +141,11 @@ func (sys *System) update() error {
 		if sys.smartInterval <= 0 {
 			sys.smartInterval = time.Hour
 		}
-		lastFetch := sys.lastSmartFetch.Load()
+		lastFetch, _ := sys.manager.smartFetchMap.GetOk(sys.Id)
 		if time.Since(time.UnixMilli(lastFetch)) >= sys.smartInterval && sys.smartFetching.CompareAndSwap(false, true) {
 			go func() {
 				defer sys.smartFetching.Store(false)
-				sys.lastSmartFetch.Store(time.Now().UnixMilli())
+				sys.manager.smartFetchMap.Set(sys.Id, time.Now().UnixMilli(), sys.smartInterval+time.Minute)
 				_ = sys.FetchAndSaveSmartDevices()
 			}()
 		}

internal/hub/systems/system_manager.go

@@ -8,6 +8,7 @@ import (
 	"github.com/henrygd/beszel/internal/hub/ws"
 
 	"github.com/henrygd/beszel/internal/entities/system"
+	"github.com/henrygd/beszel/internal/hub/expirymap"
 
 	"github.com/henrygd/beszel/internal/common"
 
@@ -40,9 +41,10 @@ var errSystemExists = errors.New("system exists")
 // SystemManager manages a collection of monitored systems and their connections.
 // It handles system lifecycle, status updates, and maintains both SSH and WebSocket connections.
 type SystemManager struct {
-	hub       hubLike                       // Hub interface for database and alert operations
-	systems   *store.Store[string, *System] // Thread-safe store of active systems
-	sshConfig *ssh.ClientConfig             // SSH client configuration for system connections
+	hub           hubLike                       // Hub interface for database and alert operations
+	systems       *store.Store[string, *System] // Thread-safe store of active systems
+	sshConfig     *ssh.ClientConfig             // SSH client configuration for system connections
+	smartFetchMap *expirymap.ExpiryMap[int64]   // Stores last SMART fetch time per system ID
 }
 
 // hubLike defines the interface requirements for the hub dependency.
@@ -58,8 +60,9 @@ type hubLike interface {
 // The hub must implement the hubLike interface to provide database and alert functionality.
 func NewSystemManager(hub hubLike) *SystemManager {
 	return &SystemManager{
-		systems: store.New(map[string]*System{}),
-		hub:     hub,
+		systems:       store.New(map[string]*System{}),
+		hub:           hub,
+		smartFetchMap: expirymap.New[int64](time.Hour),
 	}
 }
 

internal/hub/systems/systems_test_helpers.go

@@ -113,4 +113,5 @@ func (sm *SystemManager) RemoveAllSystems() {
 	for _, system := range sm.systems.GetAll() {
 		sm.RemoveSystem(system.Id)
 	}
+	sm.smartFetchMap.StopCleaner()
 }

internal/site/src/components/routes/system/smart-table.tsx

@@ -621,8 +621,8 @@ function DiskSheet({
 	const deviceName = disk?.name || unknown
 	const model = disk?.model || unknown
 	const capacity = disk?.capacity ? formatCapacity(disk.capacity) : unknown
-	const serialNumber = disk?.serial || unknown
-	const firmwareVersion = disk?.firmware || unknown
+	const serialNumber = disk?.serial
+	const firmwareVersion = disk?.firmware
 	const status = disk?.state || unknown
 
 	return (
@@ -636,24 +636,32 @@ function DiskSheet({
 						{model}
 						<Separator orientation="vertical" className="h-2.5 bg-muted-foreground opacity-70" />
 						{capacity}
-						<Separator orientation="vertical" className="h-2.5 bg-muted-foreground opacity-70" />
-						<Tooltip>
-							<TooltipTrigger asChild>
-								<span>{serialNumber}</span>
-							</TooltipTrigger>
-							<TooltipContent>
-								<Trans>Serial Number</Trans>
-							</TooltipContent>
-						</Tooltip>
-						<Separator orientation="vertical" className="h-2.5 bg-muted-foreground opacity-70" />
-						<Tooltip>
-							<TooltipTrigger asChild>
-								<span>{firmwareVersion}</span>
-							</TooltipTrigger>
-							<TooltipContent>
-								<Trans>Firmware</Trans>
-							</TooltipContent>
-						</Tooltip>
+						{serialNumber && (
+							<>
+								<Separator orientation="vertical" className="h-2.5 bg-muted-foreground opacity-70" />
+								<Tooltip>
+									<TooltipTrigger asChild>
+										<span>{serialNumber}</span>
+									</TooltipTrigger>
+									<TooltipContent>
+										<Trans>Serial Number</Trans>
+									</TooltipContent>
+								</Tooltip>
+							</>
+						)}
+						{firmwareVersion && (
+							<>
+								<Separator orientation="vertical" className="h-2.5 bg-muted-foreground opacity-70" />
+								<Tooltip>
+									<TooltipTrigger asChild>
+										<span>{firmwareVersion}</span>
+									</TooltipTrigger>
+									<TooltipContent>
+										<Trans>Firmware</Trans>
+									</TooltipContent>
+								</Tooltip>
+							</>
+						)}
 					</SheetDescription>
 				</SheetHeader>
 				<div className="flex-1 overflow-hidden p-4 flex flex-col gap-4">