NAS & RAID7 min read

Synology says "Volume Crashed": what it means and what to do

What a crashed Synology volume or storage pool means, which common reactions make it worse, and how data is recovered from SHR and Btrfs arrays.

Crypto RecoveryWallets, keys & passwords — owner-verified Ransomware RecoveryRestore without paying attackers Cloud & Storage RecoveryNAS, SAN, VMs & backups

Seeing Volume Crashed or Storage Pool Crashed in DSM is alarming, especially when the NAS holds the only copy of your business files or family photos. In most cases the data is still on the disks. What you do in the next hour matters most.

What "crashed" means

A Synology volume is built in layers. Disks are combined into a Linux software RAID (SHR is Synology's flexible version), usually managed with LVM, with a Btrfs or ext4 file system on top. "Crashed" means DSM can't assemble or mount one of those layers. Common reasons:

  • More disks failed or dropped out than the RAID level can tolerate
  • A disk failed during a rebuild (repair)
  • File-system corruption after a power cut or a failed DSM update
  • Disks removed and put back in the wrong order

What not to do

Hold off on: clicking Repair without knowing why the pool crashed, removing or reseating disks, reinstalling or resetting DSM, creating a new volume, or running file-system repair commands over SSH. Each of these writes to the disks and can overwrite the RAID and file-system metadata needed for recovery.

What to do

  1. Screenshot everything in Storage Manager: pool and volume status, each disk's status and SMART health, and the logs.
  2. Note your model, number of drives and RAID type (SHR, SHR-2, RAID 5 and so on).
  3. Check for backups: Hyper Backup targets, cloud sync, USB copies. If you have a verified, recent backup, rebuilding and restoring may be the simplest path.
  4. Shut down cleanly from DSM if no backup exists, and keep the disks in their bays in order.
  5. Get an evaluation before attempting a repair on a pool that holds unbacked-up data.

When a repair is reasonable

If exactly one disk in a redundant pool (SHR-1 or RAID 5) is marked failed, the others are healthy, and you have a backup, replacing the failed disk and repairing is normal maintenance. The risk comes when a second disk is weak: a rebuild reads every sector of the surviving disks, which is exactly when marginal drives give out.

How professional NAS recovery works

Engineers image every disk first, with cleanroom work on any that are failing. They then rebuild the RAID, LVM and Btrfs or ext4 layers offline, from those images. Your original disks are never written to. Btrfs snapshots can often bring back deleted shared folders too.

Need help with a crashed volume? See NAS data recovery or start a live chat. Tell us the model and how many drives it has.

This guide is general information, not a diagnosis of your device. Every case is different; a free evaluation tells you exactly what's wrong.

More recovery guides

Hard drives · 6 min read

Hard drive clicking? What to do, and what not to do

A clicking hard drive is usually a failing read/write head. Here's what causes it, the mistakes that make it worse, and the safest next steps.

Read guideRansomware · 8 min read

Ransomware attack: what to do in the first 24 hours

A calm, practical checklist for the first day of a ransomware incident: containment, evidence, backups, notifications and recovery options.

Read guideSSDs & flash · 6 min read

SSD not detected? Why SSD recovery is different from hard drives

Why SSDs fail without warning, how TRIM and encryption affect recovery, and what to do when an NVMe or SATA SSD disappears.

Read guide

Every hour matters. Contact us now.

Stop using the device, then talk to an engineer. Evaluation is free and your quote is fixed before we start.

Start free evaluation Call 1-347-656-8058