Large VIB file on a small static server

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Re: Troubleshooting backup size

Veeam Logoby tomhkr » Wed May 27, 2015 9:41 am

From the logfile Agent.xx.Source.yy.vmdk.log I can see:
[26.05.2015 18:02:52] < 9904> dsk| Initializing swap CTK filter for disk 'VDDK:[datastore1] VM/VM01.vmdk'. Std. block size: '524288'.
...
[26.05.2015 18:12:26] < 17308> dsk| vSphere CTK cursor reached EOF. [48848] blocks were reported as updated.

So, 48848 CBT blocks of 524288 bytes size indeed makes up 23.9 GB of data, it appears correct.

Since actual modified files at the end of days was about 2 GB, how come CBT detects so many changed blocks?
Realizing this is not a Veeam question but someone in here might have a clue on why this occurs and how to minimize this.

I have two main suspects:
Microsoft Word periodically autosaving, meaning it creates a new file on a new block and deletes the old one.
Group Policies pushing out Internet Explorer favorites with the Replace option. 10 shortcuts and 100 clients updating every 90 minutes in an average of 8 hours workday would alone give 5000 updates.
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Re: Large VIB file on a small static server

Veeam Logoby foggy » Wed May 27, 2015 3:02 pm

Tom, please review the thread above for an answer. Thanks.
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[MERGED] Large Incremental Backup/Replica

Veeam Logoby readie » Mon Nov 09, 2015 9:24 am

Hi,
We have a large fileserver (3TB) with a Backup and separate Replica each night. (I learned at VeeamON that I can do the replica from the backup files, and will be changing this soon!) The backup is reverse incremental.
Over the w/e both replica and backup are copying >500GB, and in an attempt to find out why, we have searched the drives for all files with modification date in the past three days, and there are only about 20GB of them.
Of course we are searching at the Windows level, not the VMware block level. CBT is enabled and Hotadd is being used.
Can anyone suggest other reasons why both the replica and the backup are incrementally copying this much data - it has really hit our backup window which still has several hours to run this morning, when it normally finishes about 4am (it's now about 9am UK time).
It's a puzzle rather than a serious problem, assuming it goes back to normal tomorrow.
thanks, Bob
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Re: Large Incremental Backup/Replica

Veeam Logoby PTide » Mon Nov 09, 2015 9:39 am

Hi,

What is your target repo storage and what is your Guest OS? Is there any kind of deduplication enabled in OS/Repository?

Thank you.
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Re: Large Incremental Backup/Replica

Veeam Logoby readie » Mon Nov 09, 2015 9:44 am

Repository is Windows, and so is the Guest OS. Both 2012 R2 and the Guest has dedupe set, but the repo does not (actually tried it once, but I think the 3TB files are too big for Windows dedeup?)
Bob
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Re: Large Incremental Backup/Replica

Veeam Logoby PTide » Mon Nov 09, 2015 10:20 am

Such things as guest-OS-level deduplication, antivirus software, defragmentation and other things that can change blocks might be a cause of large incrementals. Please check if any of the mentioned is applicable to your environment.

Also please take a look at this post.

Thank you.
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Re: Large Incremental Backup/Replica

Veeam Logoby TrueAlex » Mon Nov 09, 2015 2:10 pm

Are you using DFS inside guest?
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Re: Large Incremental Backup/Replica

Veeam Logoby readie » Mon Nov 09, 2015 2:52 pm

Ah - we did use DFS when we migrated the fileserver from an old VM (2008) to a new 2012 VM, and although we have switched off DFS pairing (as the old pair is dead), DFS service might still be running.
Have you experience that DFS might cause this?
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Re: Large Incremental Backup/Replica

Veeam Logoby TrueAlex » Tue Nov 10, 2015 6:42 am

DFS have some cache folders thats cause to make backup bigger, but if you dont use DFS now, probably its not your case.
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Re: Large Incremental Backup/Replica

Veeam Logoby readie » Tue Nov 10, 2015 8:43 am

I think we'll just put it down to 'one of those things'. It's gone back to normal over the past few days, and hasn't done it before. Thanks for your suggestions.
Bob
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[MERGED] Whats causing so much change

Veeam Logoby Zew » Tue Aug 09, 2016 3:16 pm

Hey all,

So I have a decent small environment, pretty well built and managed and I'm always trying to make it better. One thing I noticed odd in my backups is just how big the vibs were for a couple of my VM's.

In particular lets say a SharePoint Web Front End, usually very little changes on this server, also since the content for the server are all stored and backed up on a separate SQL server, so it's not that.

I backup this server only once a week since normally no changes are made to the layout of said content, however even in a span of a week with little AFAIK changes, the Data size is usually 25 - 50 Gigs with a Backup size with a ratio of roughly 1.9x. What could cause this much backup size with CBT enabled? Logs? I would understand windows updates would cause plenty of changed blocks, but that's only once a month.

Thoughts?
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Re: Large VIB file on a small static server

Veeam Logoby foggy » Tue Aug 09, 2016 3:46 pm

Multiple hints can be found in the thread above, as well as in this related thread.
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Re: Large VIB file on a small static server

Veeam Logoby Zew » Thu Aug 11, 2016 6:11 pm

Thanks for the merge, Sadly..

1) 2008 R2 (so no garbage collection.)

2) No AV (I have on most of my servers but removed from this one for some reason recently, so not that)

3) There are SharePoint Crawls taking place every night for indexing purposes. Again I figured most of this stuff/changes happen on the Database side, which is a different server. Unless this does similar to AV and changes Access times on a bunch of local files.

Sure is interesting.
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Re: Large VIB file on a small static server

Veeam Logoby foggy » Fri Aug 12, 2016 11:28 am

Keep in mind that even a 1 bit change would require copying the entire 1 MB (by default) block.
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Re: Large VIB file on a small static server

Veeam Logoby Gostev » Sun Aug 14, 2016 6:38 pm

Could it be that those servers are simply very fragmented?
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