FN-GM Posted September 13, 2021 Posted September 13, 2021 Hello, We are running a Server 2016 file server. We use shadow copy and it takes a copy twice a day. We noticed this seemed to stop taking new copies late last week, we could access older data without issue. I rebooted the server this evening and now all the previous versions are gone. We have a dedicated disk for shadow copy and I can see there is data consuming that disk. Does anyone have any idea what happened and if we can re-link these older shadow copies please and access the data please? Thanks
andy_b Posted September 13, 2021 Posted September 13, 2021 Never had much sucess with "missing" shadow copies. Had it a few times and never really got to the bottom of it. Windows 2003 seemed to be particulary prone to it. Have used this https://www.shadowexplorer.com/ in the past to access data that is blatantly there but invisble to "previous versions". 1
Koldov Posted September 17, 2021 Posted September 17, 2021 Don't have any experience of running the shadow copy as a standalone application, but we have a Windows Server Backup run alongside our other backup strategies (it only runs as a back-up to USB drives which are rotated and taken off-site). It usually runs ok with no problems and in all honesty I forget about it... It is actually quite handy sometimes to restore the odd file that goes missing and is actually just there to have a hardcopy in case of a DR situation for the guts of things and not have to pull down massive amounts of data from the cloud. Anyway, a couple of months ago I had errors on the server like this: About 7 of these... Event ID: 33 Source: volsnap Level: Information Description: The oldest shadow copy of volume \\?\Volume{93896cfc-d904-11dd-8cb5-001ec9ef572e} was deleted to keep disk space usage for shadow copies of volume \\?\Volume{93896cfc-d904-11dd-8cb5-001ec9ef572e} below the user defined limit. I didn't even know there was a user defined limit! And then this... Event ID: 25 Source: volsnap Level: Error Description: The shadow copies of volume \\?\Volume{93896cfc-d904-11dd-8cb5-001ec9ef572e} were deleted because the shadow copy storage could not grow in time. Consider reducing the IO load on the system or choose a shadow copy storage volume that is not being shadow copied. Pretty sure my USB drive for backups isn't being shadow copied and in fact this might not be best practise, but none of my servers have got shadow copies running on any of the drives... I'm not really sure why it felt that it needed more space (other than it must have been full) as I thought that windows backup explicitly reclaims space for the current backup by deleting older snapshots OR volsnap will automatically delete older versions. In any case, as far as I could tell all the shadow copies were gone (or at least not accessible in any explorer window)... some Googling leads me to think that "it creates a VSS snapshot on both the source and destination" and "Shadow copies are not enabled on the drive holding the backups, but it looks like the process of backing up the files causes the VSS to take a snapshot of the drive in case the files change during the backup." and "Not sure if there's a way of stopping it doing that on the destination, but looking a the size of the shadow copy storage area, that's possibly the reason for your problems. Perhaps the shadow copy is not growing quickly enough due to I/O pressure." This was also interesting but YMMV and UAYOR (it only gets interesting at the end after all the "and me" comments): https://social.technet.microsoft.com/Forums/sharepoint/en-US/204e8cce-cd1f-4ca2-852e-a5f09a77c04c/volsnap-event-id-25-and-loss-of-previous-backups?forum=windowsbackup and this https://social.technet.microsoft.com/Forums/en-US/1886c270-fc4c-41b5-b25f-3a8d52a4a8a7/data-loss-event-id-25-quotthe-shadow-copies-on-volume-e-were-deleted-because-shadow-copy-storage
Koldov Posted September 17, 2021 Posted September 17, 2021 (edited) I found some info on using CLI to delete old shadow copies and do this regularly now! From MS: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/wbadmin-delete-systemstatebackup (sorry, these are adverts for AOMEI backup, but with more info on why it happens).... https://www.ubackup.com/windows-server/windows-server-backup-not-deleting-old-backups-8523.html https://www.ubackup.com/wbadmin/delete-backup-4348.html Edited September 17, 2021 by Koldov
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