fix(agent): fix QNAP MD RAID arrays incorrectly reported as FAILED (#2065)

agent/mdraid_linux.go

@@ -17,15 +17,17 @@ import (
 var mdraidSysfsRoot = "/sys"
 
 type mdraidHealth struct {
-	level         string
-	arrayState    string
-	degraded      uint64
-	raidDisks     uint64
-	syncAction    string
-	syncCompleted string
-	syncSpeed     string
-	mismatchCnt   uint64
-	capacity      uint64
+	level          string
+	arrayState     string
+	degraded       uint64
+	faultyDisks    uint64
+	populatedDisks uint64
+	raidDisks      uint64
+	syncAction     string
+	syncCompleted  string
+	syncSpeed      string
+	mismatchCnt    uint64
+	capacity       uint64
 }
 
 // scanMdraidDevices discovers Linux md arrays exposed in sysfs.
@@ -92,6 +94,9 @@ func (sm *SmartManager) collectMdraidHealth(deviceInfo *DeviceInfo) (bool, error
 	if health.degraded > 0 {
 		attrs = append(attrs, &smart.SmartAttribute{Name: "Degraded", RawValue: health.degraded})
 	}
+	if health.faultyDisks > 0 {
+		attrs = append(attrs, &smart.SmartAttribute{Name: "FaultyDisks", RawValue: health.faultyDisks})
+	}
 	if health.syncAction != "" {
 		attrs = append(attrs, &smart.SmartAttribute{Name: "SyncAction", RawString: health.syncAction})
 	}
@@ -152,6 +157,7 @@ func readMdraidHealth(blockName string) (mdraidHealth, bool) {
 	if val, ok := utils.ReadUintFile(filepath.Join(mdDir, "degraded")); ok {
 		out.degraded = val
 	}
+	out.faultyDisks, out.populatedDisks = countMdraidMemberStates(blockName, mdraidSysfsRoot)
 	if val, ok := utils.ReadUintFile(filepath.Join(mdDir, "mismatch_cnt")); ok {
 		out.mismatchCnt = val
 	}
@@ -177,7 +183,19 @@ func mdraidSmartStatus(health mdraidHealth) string {
 	case "resync", "recover", "reshape":
 		return "WARNING"
 	}
+	// Use actual faulty member count rather than the degraded counter, which
+	// equals raid_disks minus active_disks. On QNAP systems raid_disks may be
+	// set to a large value (e.g. 32) while only a few slots are ever used,
+	// making degraded misleadingly large despite zero failed disks.
+	if health.faultyDisks > 0 {
+		return "FAILED"
+	}
 	if health.degraded > 0 {
+		if isSparseSlotDegraded(health) {
+			// A sysfs snapshot cannot distinguish reserved slots from a removed
+			// member on sparse arrays, so report the ambiguity as a warning.
+			return "WARNING"
+		}
 		return "FAILED"
 	}
 	if health.mismatchCnt > 0 {
@@ -196,6 +214,43 @@ func mdraidSmartStatus(health mdraidHealth) string {
 	return "UNKNOWN"
 }
 
+// countMdraidMemberStates reads member device directories under
+// block/<name>/md and returns how many are explicitly marked "faulty", plus
+// how many are populated at all (regardless of state). populatedDisks lets
+// callers distinguish RAID slots that were never used (QNAP reserves far
+// more raid_disks than it ever populates) from members that went missing.
+func countMdraidMemberStates(blockName, root string) (faultyDisks, populatedDisks uint64) {
+	devDir := filepath.Join(root, "block", blockName, "md")
+	entries, err := os.ReadDir(devDir)
+	if err != nil {
+		return 0, 0
+	}
+	for _, ent := range entries {
+		if !strings.HasPrefix(ent.Name(), "dev-") {
+			continue
+		}
+		populatedDisks++
+		statePath := filepath.Join(devDir, ent.Name(), "state")
+		state := utils.ReadStringFile(statePath)
+		if strings.Contains(state, "faulty") {
+			faultyDisks++
+		}
+	}
+	return faultyDisks, populatedDisks
+}
+
+// isSparseSlotDegraded reports whether a non-zero "degraded" count may be
+// explained by RAID slots that were never populated. QNAP configures system
+// arrays with raid_disks set to a large fixed maximum (e.g. 32) far beyond the
+// handful of slots it ever populates, so sparse slots outnumber populated ones.
+func isSparseSlotDegraded(health mdraidHealth) bool {
+	if health.populatedDisks == 0 || health.raidDisks <= health.populatedDisks {
+		return false
+	}
+	sparseSlots := health.raidDisks - health.populatedDisks
+	return sparseSlots > health.populatedDisks
+}
+
 // isMdraidBlockName matches /dev/mdN-style block device names.
 func isMdraidBlockName(name string) bool {
 	if !strings.HasPrefix(name, "md") {