Overview

Rebuilds place sustained load on disks. Good preparation and reduced workload lower the chance of a second failure.

Preparation checklist

Work through these items before you start.

• Verify you have a current backup and recent snapshots
• Run extended S M A R T tests on remaining drives
• Update DSM and controller firmware if recommended
• Schedule the rebuild during low activity hours
• Disable heavy background tasks such as thumbnailing or large sync jobs

During the rebuild

Keep the system cool and workloads minimal.

• Monitor drive temperatures and keep airflow unobstructed
• Avoid large file moves and major package updates
• Track progress in Storage Manager and system logs
• Have a cold spare ready in case another drive shows errors

Post rebuild checks

Confirm the array is healthy before resuming heavy work.

• Run a parity scrub or data consistency check
• Review S M A R T results and reallocated sector counts
• Verify backups have resumed and complete successfully
• Document the rebuild time and any anomalies

Prevention and ongoing care

Reduce future rebuild risk with simple routines.

• Keep a spare drive on hand and replace suspect disks proactively
• Plan capacity so arrays do not run near full
• Consider RAID 6 for larger arrays to tolerate a second failure

FAQs

Helpful clarifications for planning rebuilds.

• Can I use the NAS during rebuild
• Light use is fine, avoid heavy workloads
• How long will it take
• Depends on capacity, model, and load
• Should I switch to SHR or RAID 6
• Choose based on bay count, risk, and growth plans