Synology storage pool crash

If your Synology storage pool is displayed as Degraded or Dangerous, most likely there are some problems with a system partition or with one or several member disks. When such a situation occurs, from the user point of view it looks like it is impossible to get access to the data stored in the NAS device. Synology NASes have a built-in fixing tool like the Repair function. However, this function works only in case of a logical failure, rather than for cases where damaged drives involved. Moreover, on the official Synology web-site you can find read that the Repair function ┬źdoes not guarantee data on crashed volumes will be rescued┬╗. So, if the data is really important, it is better first to get access to the data and only then use the Repair function. The same rule applies for cases when the storage pool became degraded due to a disk failure. Of course, NAS arrays have been designed to make the process of replacing disks as simple and smooth as possible; however, there are a lot of sad stories in the web describing situations when something went wrong during the disk replacement resulting in data loss.

Synology pool is degraded

How to recover data if Synology storage pool crashed


  • To recover data you need to prepare an additional storage device equal to the size of the data stored on the Synology device. That is, if your Synology was 6 TB, but in fact only 2 TB was stored on it, then 2 TB disk will be enough for you.
  • In order to connect drives from Synology, you may need to buy USB-to-SATA adapters, along with power supplies.
  • How to connect the NAS disks to a PC via USB
  • You will also need to use data recovery software which is capable of recovering data from btrfs (almost all modern Synology devices use btrfs filesystem, rather than EXT), for example ReclaiMe File Recovery.

Recovery workflow

  1. Remove the disks from your Synology. It is impossible to recover files from Synology having the disks inside, because the software must directly access the hard drives but the NAS does not provide this capability.
  2. Connect the disks to a PC running Windows. It is recommended to connect the drives directly to the motherboard using these cables
    Check the quality of the recovery in ReclaiMe
    Generally, USB is less stable. Another problem is, if there is a bad block on one of the source drives, the USB-to-SATA bridges tend to lock up entirely after encountering a bad block. However, if this is not possible, or the motherboard does not have enough free ports, then you can use USB-to-SATA adapters.
  3. Download and install ReclaiMe File Recovery software.
  4. Select the Synology volume you need to recover and click Start. Most likely, the volume will be under the BTRFS section.
  5. Wait until ReclaiMe File Recovery starts bringing files and then check the quality of the recovery using the Preview.
Check the quality of the recovery in ReclaiMe

All the steps on video

Still have questions?