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Synthetic backups & true image - do they work with DFS?

Created: 20 Apr 2012 | 4 comments

My understanding of true image is that if I restore an incremental backup from (say) Wednesday night, the BE will re-build the restored folder from the last full backup (previous Friday) plus any of the incremental backups that happen to contain files from the folder been restored.

Is my basic understanding correct here?

If so, then I think we've got a problem but will explain more before I go and make a fool of myself in raising a support call.

For the purposes of this post, we are backing up a DFS folder system and a plain-old-folder system using deduplication storage.

If I restore the Wed backup from the plain-old-folder system, I do indeed get back a complete set of files, i.e. it restored from the last backup (even though I didn't select it) plus the incrementals. That works a treat.

But when I do the same from the the DFS folder system, all I get are the files in last incremental backup which is definately not what I was expecting.

It's almost as if (and I HOPE this isn't the reason) True Image cannot be used with DFS file systems.

Any thoughts?

Thanks, Rob

PS. The restores are being done to a local folder, not the original location as these are tests.

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robnicholson's picture

Knowing the acronym ABDO allowed me to do a more targetted search and found this one:

Nice one Symantec! Half a solution again...


robnicholson's picture

Would anyone from Symantec like to comment on when this deficiency will be corrected? The use of DFSR is hardly an usual one with many people using it for DR purposes/failover and for it to not work with so-called Advanced Disk Backup is a big omission.

Is it fixed in BE 2012?

Cheers, Rob.

Colin Weaver's picture

It is more of an enhancement than a defect that needs fixing as Backup Exec was never designed to do what you want.

I suspect some of the reasoning is more of a limitation against the way Shadow Copy Components work in the Operating System than just a Backup Exec limitation making it difficult to achieve without code change in the operating system.

Whatever the cause, I just checked the engineering escalation and it is not a feature available in BE 2012, and there is no confirmation of any specific target version either.

robnicholson's picture

It is more of an enhancement than a defect that needs fixing as Backup Exec was never designed to do what you want.

That nearly made the choke! This is indicative of all that's going wrong with Backup Exec. Definition of a defect:

The lack of something necessary or desirable for completion or perfection; a deficiency

If you sell Advanced Disk Backup then it should jolly well work with a very common technology used in many sites for failover purposes. 90% of our data is on DFSR and the rest is Exchange which can't use it either.

It belies the way BE has evolved over the years into the rather complicated mess it is today. Yes I'm annoyed. We've spent money on the advanced disk backup license and it's useless.

I can't think of any technical reason why it couldn't work. Yes, I know you changed the way DFSR is backed up (and not to universal acclaim as it's now a lot slower) in a service pack a while back and I suspect suspect the change wasn't fully thought through. If your engineering team would like to explain exactly why it doesn't work, then I'll shut up.

The rebuilding of a synthetic restore is, I assume, something done entirely by the media server so why DFSR would effect it is perplexing.