Backing up a folder on ReFS disk results in VSS snapshot error

What happens when you run the following command in an elevated CMD prompt?

vssadmin list writers

vssadmin list writers

Tommy, thank you for your reply!  I get the following results with no errors:

C:\Users\administrator>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Writer name: 'Task Scheduler Writer'
   Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
   Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b}
   State: [1] Stable
   Last error: No error

Writer name: 'VSS Metadata Store Writer'
   Writer Id: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06}
   Writer Instance Id: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93}
   State: [1] Stable
   Last error: No error

Writer name: 'Performance Counters Writer'
   Writer Id: {0bada1de-01a9-4625-8278-69e735f39dd2}
   Writer Instance Id: {f0086dda-9efc-47c5-8eb6-a944c3d09381}
   State: [1] Stable
   Last error: No error

Writer name: 'System Writer'
   Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
   Writer Instance Id: {dc4a59a6-8d06-4e6a-85a3-366363c32dd4}
   State: [1] Stable
   Last error: No error

Writer name: 'ASR Writer'
   Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
   Writer Instance Id: {f1300fb1-3fcc-41cf-a3a2-3ae4c6d217f8}
   State: [1] Stable
   Last error: No error

Writer name: 'Dedup Writer'
   Writer Id: {41db4dbf-6046-470e-8ad5-d5081dfb1b70}
   Writer Instance Id: {54e599ad-728f-4c95-8f15-d5b5c5ade8d5}
   State: [1] Stable
   Last error: No error

Writer name: 'Registry Writer'
   Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
   Writer Instance Id: {f8108b16-0ae0-4756-b15b-fdb04cd21100}
   State: [1] Stable
   Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
   Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
   Writer Instance Id: {dcea8157-bbd1-45e0-86b4-bd66f5f3bd93}
   State: [1] Stable
   Last error: No error

Writer name: 'COM+ REGDB Writer'
   Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
   Writer Instance Id: {0bee01d8-8f64-41ab-8d3e-965d86e55b3c}
   State: [1] Stable
   Last error: No error

Writer name: 'WMI Writer'
   Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
   Writer Instance Id: {3cd59406-8748-4a86-9158-ee87fb7ca3ef}
   State: [1] Stable
   Last error: No error

Thanks!

-s.

​@sul , I found this forum post which shows an error very similar to the one you’re receiving.

In their case, it was Manage Engine Anti-Ransomware functionality that was conflicting with the VSS snapshots.

I’d check to see if you have the same or similar potential conflicting software on your system.

Tommy, thank you for the post reference. The server is pretty bare bones and it does not have third party software like the above  other than the Veeam related apps and Chrome & Edge browsers.  The server is running on Windows Server 2022 Standard.  For endpoint protection, the server uses Windows Security that’s part of Windows.

Thank you!

Hi Chris, thank you for the tip.  I did run vssadmin list writers and there were no errors.  The log did not offer anything useful, unfortunately.  I went ahead and opened up case 07650444 and hoping for a fix.  I use the community version of Veeam B&R, so I am a bit doubtful whether anyone will chime in, but let’s see... Crossing fingers!

thanks!

-s.

Hello,

In case it helps anyone having a similar challenge, I am finding that Veeam has a disk size limitation of 64 terabytes.  AFAIK, Veeam does not know how to check for this threshold.  Therefore, even if as a courtesy, Veeam cannot alert users about this condition--it just throws an error when trying to backup something greater than 64 TB, which by then I think is too late.  I was able to work around this limitation by temporarily moving all files from the 150+ TB disk over to a different disk, deleting the 150+ TB ReFs volume, recreating it with three smaller ReFS partitions of about 55 TB each and then moving the files back into the newly created partitions.  Backups of these smaller partitions seem to be going well so far!

Also, since Windows server supports ReFS mount points, all three partitions are mounted onto a single volume, e.g. F:\mnt1, F:\mnt2, F:\mnt3 for ease of access by end-users.  The caveat is that if you want Veeam to backup certain volumes, as opposed to backing up all volumes, each mount point has to be explicitly added to the Objects list (F:\mnt1, F:\mnt2, etc.) when creating a backup job. You cannot simply add F:\ as an object and expect each Windows mount point to be backed up.

Thank you to all who chimed in to help earlier.

-sul.

Glad to hear you were able to get the issue addressed.  Yeah that 64TB limit they need to put in some type of message or warning for it.