Q: What happens if my NAS hard drive fails?

2026-11-03

---

#NAS #hard drive #FAQ

If a hard drive in your ASUSTOR NAS fails, whether your data remains accessible depends on the RAID configuration and the number of failed drives.

RAID configurations such as RAID 1, RAID 5, RAID 6, and RAID 10 provide fault tolerance, allowing the NAS to continue operating under certain drive failure conditions.

However, RAID is not a substitute for regular data backups.

Steps to take after a hard drive failure

1. Check the drive and RAID status: Log in to ADM and open Storage Manager to identify the failed drive and check the status of the RAID volume.

2. Replace the failed drive: If the RAID volume is in a degraded state and supports rebuilding, replace the failed drive with a compatible one. Confirm that your NAS model supports hot-swapping before replacing a drive while the NAS is powered on.

3. Monitor the rebuild progress: After replacing the failed drive, the RAID rebuild process should start automatically if the configuration and RAID status allow it. You can monitor the progress in Storage Manager.

Impact of Different RAID Levels

• RAID 0: Provides improved performance but no fault tolerance. If one drive fails, the entire RAID volume may become inaccessible.

• RAID 1: Mirrors data across drives. If one drive fails, data remains accessible through the remaining healthy drive, provided the RAID configuration can tolerate the failure.

• RAID 5: Distributes data and parity across multiple drives. It can tolerate one drive failure.

• RAID 6: Uses dual parity and can tolerate up to two drive failures.

• RAID 10: Combines mirroring and striping. Fault tolerance depends on which drives fail.

Important Notes

• Back up important data: If your RAID volume is degraded but still accessible, make sure important data is backed up before proceeding with recovery operations.

• Avoid heavy disk activity: During RAID rebuilding, avoid unnecessary disk-intensive operations that may affect rebuild performance.

• Contact technical support: If multiple drives have failed, the RAID volume is inaccessible, or the rebuild cannot start, contact ASUSTOR technical support before attempting further recovery operations.

For more information, please refer to ASUSTOR College.