Volume is displayed as RAW. The data is corrupted due to the REFS partitions. No access to the volumes anymore. How do I restore the volumes (without data loss)?

Question

The volumes connected via iSCSI from an MSA to our backup server are partitioned via ReFS. The drives showed up as RAW over the weekend and are no longer available. As a result, backups to the volumes no longer work either.

The error message in the event viewer is as follows:

Event 135, ReFS :

"The volume "E:" is formatted as ReFS, but cannot be mounted by ReFS. The status "{volume defective}" was detected by ReFS. The file system structure on the volume is damaged and unusable.

Run the CHKDSK utility for the %hs volume." "

Without formatting the disk, we can no longer mount the volume.

There was a similar case in 2022: https://techcommunity.microsoft.com/t5/windows-server-for-it-pro/refs-volume-appears-raw-version-doesn-t-match-expected-value/m-p/3058652/page/4

This has already been verified and unfortunately is not the case for us.

We would like to recover the drives without data loss.

Answer 1

First of all, make a copy of the entire LUN (if possible) using trivial disk cloning or P2V software like Microsoft Disk2VHD https://aka.ms/disk2vhdor free V2V Converter https://www.starwindsoftware.com/starwind-v2v-converter to avoid damaging your only copy even further.

After that part is done, proceed with using ReFSUtil and perform a quick scan of your damaged LUN to see if that helps. You should get a list of recoverable files.

If a quick scan does not find anything, proceed with a full scan. Depending on your LUN size, it may take a substantial amount of time, so it would be best to leave it running overnight. Make sure you have enough free storage to copy recovered data to.

More information about using Microsoft ReFSUtil can be found here https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/refsutil.