The knowledge base says that a volume crash caused by drive errors or file system errors cannot be repaired. What you can do depends on the situation:
- If the system cannot be powered on because of drive failure issues, the KB says to fix the drive failure and retrieve the data from your drives.
- If you can power on and sign in, but the data cannot be read via File Station, the KB says to contact your local data rescue companies for assistance.
- If you can power on and sign in and the data can still be read via File Station, do not power off the system and follow the recovery guidance.
For storage shown as degraded in Synology High Availability (SHA), the guide recommends:
1. On the active server, go to Storage Manager or Synology High Availability > Storage to identify which storage pool the degraded volume belongs to.
2. Go to Synology High Availability > Storage > HDD/SSD to find the degraded drive and replace it with a healthy drive.
3. Go to Synology High Availability > Storage, select the crashed volume, and click Repair.
For read-only storage space or SSD cache, the guide says to:
1. Identify which storage pool is read-only in Storage Manager or Synology High Availability > Storage > Volume.
2. Find the read-only drive in Synology High Availability > Storage > HDD/SSD and replace it with a healthy drive.
3. Select the crashed volume and click Repair.
For crashed storage in Storage Manager, the KB says you can no longer repair it by yourself and should review the volume-crash causes and troubleshooting articles.
So, based on the knowledge base:
- Degraded storage may be repairable after replacing the bad drive.
- Crashed volume caused by drive/file system errors is not repairable from the KB’s self-service steps, and data recovery depends on whether the system/data is still readable.
Sources used: [1] [7] [10]