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oj88

What causes client backup database corruption?

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oj88

I have a few client machines with failed, interrupted, or otherwise incomplete backups due to clients being shutdown or rebooted before the backup completes. Of course, Microsoft's removal of the "Backup Running" tray notification after WHSv1 didn't help either and I don't see how MS thought that THAT was an improvement on WHSv2.

 

Anyway, more to the topic. So, I have a few of these "Failed" client backups that I tried deleting, just for the purpose of housekeeping. They get deleted all right and no longer appears after the cleanup task does its job on Sat/Sun midnight. At this point, only the "Successful" backups are retained and the backup logs looks nice and tidy.

 

However, running a backup on those clients thereafter will almost always fail and the server will complain of a corrupt client backup database. I run the repair tool but I end up with even more Incomplete backups.

 

Is there a best practice for deleting old or failed client backups without having to go through this?

 

Just to add: If I leave everything alone to the server's backup retention policy, the backup database does not get damaged. But what is the point of having the ability to manually delete backups when doing so would have an adverse effect on the database?

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diehard

There is a free version of Home Server Status add-in that will show a counter when backups are in progress. I believe Light's Out will pop a warning if you try and shut down a PC during a backup. This is the case with WHSv1 Light's Out, not sure about WHS2011 Light's Out so give it a read or try.

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ikon

I also believe this is a case of "leave well enough alone". OK, you may end up with a few incomplete backups in the list.... ignore them. IMHO, it really doesn't matter if the Delete feature doesn't work as it should, because it's not a big deal if there are incomplete backups included.

 

In the larger scheme, if MS has to decide whether to devote resources to fixing something like Storage Spaces or the Backup Delete feature, I want them to fix Storage Spaces.

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oj88

Yes, quite familiar with the 'don't fix it if it ain't broke' cliche. It's just more of a general inquiry why a seemingly straightforward feature would break the database.

 

I'm glad Microsoft hasn't built a car because by their logic, it would start spitting out engine oil if you drove it through a car wash. ;)

 

But anyway, I'm also practical. So if it translates to a bit more stability, I'd let WHS take care of the backup database from now on.

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ikon

I suspect the backup database isn't "seemingly straightforward" at all. With Single Instance Storage I suspect it is quite a complex task to keep track of all the blocks of data and I suspect that this involves some pretty complex Linked List structures. Linked Lists are notorious for becoming corrupt, which may be what's going on here.

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timekills

I doubt this is the cause, but 've inadvertently removed PCs from backup and retained the files for archive. The archived folders are notorious for causing backup corruption.

 

On that note, as PITA as it is, if you want to be anal about it you could remove the PCs completely and re-add them. That typically cleans up any mis-linked files and allows for a new, complete backup. Just don't archive the backup data when removing the PC...

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oj88

Thanks for the valuable insights. I love this forum. :)

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Drashna Jaelre

I also believe this is a case of "leave well enough alone". OK, you may end up with a few incomplete backups in the list.... ignore them. IMHO, it really doesn't matter if the Delete feature doesn't work as it should, because it's not a big deal if there are incomplete backups included.

 

In the larger scheme, if MS has to decide whether to devote resources to fixing something like Storage Spaces or the Backup Delete feature, I want them to fix Storage Spaces.

I.... ah.... would rather they fix the backup engine. ;)

 

I have a few client machines with failed, interrupted, or otherwise incomplete backups due to clients being shutdown or rebooted before the backup completes. Of course, Microsoft's removal of the "Backup Running" tray notification after WHSv1 didn't help either and I don't see how MS thought that THAT was an improvement on WHSv2.

 

Anyway, more to the topic. So, I have a few of these "Failed" client backups that I tried deleting, just for the purpose of housekeeping. They get deleted all right and no longer appears after the cleanup task does its job on Sat/Sun midnight. At this point, only the "Successful" backups are retained and the backup logs looks nice and tidy.

 

However, running a backup on those clients thereafter will almost always fail and the server will complain of a corrupt client backup database. I run the repair tool but I end up with even more Incomplete backups.

 

Is there a best practice for deleting old or failed client backups without having to go through this?

 

Just to add: If I leave everything alone to the server's backup retention policy, the backup database does not get damaged. But what is the point of having the ability to manually delete backups when doing so would have an adverse effect on the database?

 

 

Absolutely worst case here, backup the "Client Backup Database" folder, and wipe it. Start from scratch.

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ikon

OK, Mr. DrivePool :D LOL :D

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jmwills

Backup the backup. That's like 3-2-1 squared.

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