A RAID array protects your data against a single drive failure — but it only works if you know its current state. A degraded RAID (one drive failed, running on reduced protection) is as dangerous as no RAID at all because a second failure will cause data loss. Checking RAID health regularly is non-negotiable. Here is how to do it on Windows Server.
Understanding RAID States
Before checking, know the states you might encounter:
- Optimal / Healthy: all drives present, no errors, full redundancy in place
- Degraded: one or more drives have failed but the array is still running. You have no redundancy — replace the failed drive immediately.
- Rebuilding / Resyncing: a replacement drive has been inserted and the array is rebuilding parity or mirroring data. This can take hours. The server is working but under increased load and still has reduced redundancy until complete.
- Failed / Offline: too many drives have failed, the array is gone, and data is inaccessible or lost
Hardware RAID — Check via iDRAC or iLO
If your server uses a hardware RAID controller (Dell PERC, HP Smart Array, Lenovo RAID, LSI MegaRAID), the best place to check is the out-of-band management interface:
- Dell iDRAC: log in → Storage → Virtual Disks. Shows array status, RAID level, and individual drive health. Email alerts can be configured here for drive failures.
- HP iLO: log in → System Information → Storage. Shows the Smart Array controller, logical drives, and physical drive status.
- Front panel LED: an amber drive bay light means the RAID controller has flagged that specific drive for replacement
Hardware RAID — Check via Manufacturer Software
Most hardware RAID controllers have a management utility that runs on the server OS:
- Dell OpenManage Server Administrator (OMSA): provides full RAID status, drive SMART data, and email alerting. Download from Dell’s support site.
- HP Smart Storage Administrator (SSA): for HP ProLiant servers. Shows logical drive status, physical drive health, and allows online capacity expansion.
- MegaRAID Storage Manager: for LSI/Broadcom-based controllers. Shows controller status, virtual disks, and physical drives.
These tools are more detailed than iDRAC/iLO and allow RAID configuration changes while the server is running.
Software RAID (Windows Storage Spaces) — Check via PowerShell
If you are using Windows Storage Spaces (software RAID) rather than a hardware controller:
# Check storage pool health
Get-StoragePool | Select-Object FriendlyName, HealthStatus, OperationalStatus
# Check virtual disks (the RAID volumes)
Get-VirtualDisk | Select-Object FriendlyName, HealthStatus, OperationalStatus, ResiliencySettingName
# Check individual physical disks in the pool
Get-PhysicalDisk | Select-Object FriendlyName, HealthStatus, OperationalStatus, UsageAll three should show Healthy and OK. A Warning or Degraded status means a drive in the pool has failed or is failing.
Software RAID — Check via Server Manager
- Open Server Manager → File and Storage Services → Storage Pools
- The status column shows whether each pool is Healthy, Warning, or Degraded
- Click a pool to see the virtual disks within it and their individual health status
Windows Disk Management — Basic Mirror/RAID-5 Check
For legacy Windows software RAID (mirrored or striped volumes set up in Disk Management):
- Open Disk Management (Win + X → Disk Management)
- Look for volumes with status Failed Redundancy — this means one drive in a mirror has failed
- A healthy mirror shows Healthy in the volume status
Setting Up RAID Health Alerts
Do not rely on checking manually — configure alerts so you are notified immediately when a drive fails:
- iDRAC/iLO email alerts: configure SMTP settings in the management interface to send emails on hardware events
- Windows Storage Spaces: use Storage Spaces event IDs in Event Viewer (Event ID 6, 7, 8 in the Storage Spaces log) with a custom task to send email on trigger
- Monitoring software: PRTG, Nagios, Zabbix, and similar tools all have RAID health sensors that alert on degraded arrays
