Fix NVMe serial display and improve pool health logic

- Fix physical drive serial number display in dashboard
- Improve pool health calculation for arrays with multiple disks
- Support proper tree symbols for multiple parity drives
- Read git commit hash from /var/lib/cm-dashboard/git-commit for Build display

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.156"
+version = "0.1.157"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.156"
+version = "0.1.157"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -324,7 +324,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.156"
+version = "0.1.157"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.156"
+version = "0.1.157"
 edition = "2021"
 
 [dependencies]

agent/src/collectors/disk.rs

@@ -639,10 +639,19 @@ impl DiskCollector {
         }).collect();
         
         // Calculate overall pool health string and status
-        let (pool_health, health_status) = match (failed_data, failed_parity) {
-            (0, 0) => ("healthy".to_string(), cm_dashboard_shared::Status::Ok),
-            (1, 0) | (0, 1) => ("degraded".to_string(), cm_dashboard_shared::Status::Warning),
-            _ => ("critical".to_string(), cm_dashboard_shared::Status::Critical),
+        // SnapRAID logic: can tolerate up to N parity drive failures (where N = number of parity drives)
+        // If data drives fail AND we've lost parity protection, that's critical
+        let (pool_health, health_status) = if failed_data == 0 && failed_parity == 0 {
+            ("healthy".to_string(), cm_dashboard_shared::Status::Ok)
+        } else if failed_data == 0 && failed_parity > 0 {
+            // Parity failed but no data loss - degraded (reduced protection)
+            ("degraded".to_string(), cm_dashboard_shared::Status::Warning)
+        } else if failed_data == 1 && failed_parity == 0 {
+            // One data drive failed, parity intact - degraded (recoverable)
+            ("degraded".to_string(), cm_dashboard_shared::Status::Warning)
+        } else {
+            // Multiple data drives failed OR data+parity failed = data loss risk
+            ("critical".to_string(), cm_dashboard_shared::Status::Critical)
         };
         
         // Calculate pool usage status using config thresholds

agent/src/collectors/nixos.rs

@@ -83,14 +83,25 @@ impl NixOSCollector {
         std::env::var("CM_DASHBOARD_VERSION").unwrap_or_else(|_| "unknown".to_string())
     }
 
-    /// Get NixOS system generation (build) information
+    /// Get NixOS system generation (build) information from git commit
     async fn get_nixos_generation(&self) -> Option<String> {
-        match Command::new("nixos-version").output() {
-            Ok(output) => {
-                let version_str = String::from_utf8_lossy(&output.stdout);
-                Some(version_str.trim().to_string())
+        // Try to read git commit hash from file written during rebuild
+        let commit_file = "/var/lib/cm-dashboard/git-commit";
+        match fs::read_to_string(commit_file) {
+            Ok(content) => {
+                let commit_hash = content.trim();
+                if commit_hash.len() >= 7 {
+                    debug!("Found git commit hash: {}", commit_hash);
+                    Some(commit_hash.to_string())
+                } else {
+                    debug!("Git commit hash too short: {}", commit_hash);
+                    None
+                }
+            }
+            Err(e) => {
+                debug!("Failed to read git commit file {}: {}", commit_file, e);
+                None
             }
-            Err(_) => None,
         }
     }
 }

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.156"
+version = "0.1.157"
 edition = "2021"
 
 [dependencies]

dashboard/src/ui/widgets/system.rs

@@ -368,12 +368,8 @@ impl SystemWidget {
             // Pool header line with type and health
             let pool_label = if pool.pool_type == "drive" {
                 // For physical drives, show the drive name with temperature and wear percentage if available
-                // Look for any drive with temp/wear data (physical drives may have drives named after the pool)
-                let drive_info = pool.drives.iter()
-                    .find(|d| d.name == pool.name)
-                    .or_else(|| pool.drives.first());
-
-                if let Some(drive) = drive_info {
+                // Physical drives only have one drive entry
+                if let Some(drive) = pool.drives.first() {
                     let mut drive_details = Vec::new();
                     if let Some(temp) = drive.temperature {
                         drive_details.push(format!("T: {}°C", temp as i32));
@@ -381,11 +377,11 @@ impl SystemWidget {
                     if let Some(wear) = drive.wear_percent {
                         drive_details.push(format!("W: {}%", wear as i32));
                     }
-                    
+
                     if !drive_details.is_empty() {
-                        format!("{} {}", pool.name, drive_details.join(" "))
+                        format!("{} {}", drive.name, drive_details.join(" "))
                     } else {
-                        pool.name.clone()
+                        drive.name.clone()
                     }
                 } else {
                     pool.name.clone()
@@ -443,7 +439,9 @@ impl SystemWidget {
                 lines.push(Line::from(total_spans));
 
                 // Data drives - at same level as parity
+                let has_parity = !pool.parity_drives.is_empty();
                 for (i, drive) in pool.data_drives.iter().enumerate() {
+                    let is_last_data = i == pool.data_drives.len() - 1;
                     let mut drive_details = Vec::new();
                     if let Some(temp) = drive.temperature {
                         drive_details.push(format!("T: {}°C", temp as i32));
@@ -458,16 +456,19 @@ impl SystemWidget {
                         format!("Data_{}: {}", i + 1, drive.name)
                     };
 
+                    // Last data drive uses └─ if there's no parity, otherwise ├─
+                    let tree_symbol = if is_last_data && !has_parity { "  └─ " } else { "  ├─ " };
                     let mut data_spans = vec![
-                        Span::styled("  ├─ ", Typography::tree()),
+                        Span::styled(tree_symbol, Typography::tree()),
                     ];
                     data_spans.extend(StatusIcons::create_status_spans(drive.status.clone(), &drive_text));
                     lines.push(Line::from(data_spans));
                 }
 
-                // Parity drives - last item
+                // Parity drives - last item(s)
                 if !pool.parity_drives.is_empty() {
-                    for drive in &pool.parity_drives {
+                    for (i, drive) in pool.parity_drives.iter().enumerate() {
+                        let is_last = i == pool.parity_drives.len() - 1;
                         let mut drive_details = Vec::new();
                         if let Some(temp) = drive.temperature {
                             drive_details.push(format!("T: {}°C", temp as i32));
@@ -482,8 +483,9 @@ impl SystemWidget {
                             format!("Parity: {}", drive.name)
                         };
 
+                        let tree_symbol = if is_last { "  └─ " } else { "  ├─ " };
                         let mut parity_spans = vec![
-                            Span::styled("  └─ ", Typography::tree()),
+                            Span::styled(tree_symbol, Typography::tree()),
                         ];
                         parity_spans.extend(StatusIcons::create_status_spans(drive.status.clone(), &drive_text));
                         lines.push(Line::from(parity_spans));

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.156"
+version = "0.1.157"
 edition = "2021"
 
 [dependencies]