Monthly backup without CBT

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Monthly backup without CBT

Veeam Logoby Lasr » Fri Jan 29, 2016 10:40 am

Hi,

after all these issues with CBT I'm asking myself if it would be better to disable CBT / in our monthly backup. If I would like to change my montly active full to get as most consistent backups what would I have to change?


This is what I think:

Exclude deleted file blocks: I would disable this just to be sure, that there is no mismatch and anything goes wrong.

Exclude swap files: This should be irrelevant because its just about backup swap disks (.vswp) that are located in the VM directory. So I would still use it.

CBT: I would disable both CBT options located under the vSphere Tab, to achive that veeam never use CBT for my monthly backup.


Are my thinkings right or is there anything else I have to do, to achieve this?


Regards
lasr
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Re: Monthly backup without CBT

Veeam Logoby PTide » Fri Jan 29, 2016 10:51 am

Hi,

Exclude deleted file blocks, Exclude swap files:
These features have nothing to do with CBT. Deleted file blocks are excluded based on MFT content.

CBT: I would disable both CBT options located under the vSphere Tab, to achive that veeam never use CBT for my monthly backup.
No need to do that if your monthly backup is active full - during active backup the whole VM disk is read anyway.
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Re: Monthly backup without CBT

Veeam Logoby Lasr » Fri Jan 29, 2016 11:00 am

PTide wrote:No need to do that if your monthly backup is active full - during active backup the whole VM disk is read anyway.

This is exactly was I thought too, but if I take a look in my logs then I see:

Image

So why CBT is logged if its not used and some HDDs got not read completly :shock: :?:

Edit: The logs are from a v8 job, so there was no exclusion for deleted blocks.
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Re: Monthly backup without CBT

Veeam Logoby PTide » Fri Jan 29, 2016 12:30 pm 1 person likes this post

So why CBT is logged if its not used and some HDDs got not read completly
Please disregard what was said in my previous post about active full and CBT - CBT data is used in Active Full too.

So, disabling CBT in your monthly full will prevent you backup from corruption, indeed.

Sorry for misguidance.

Thank you.
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Re: Monthly backup without CBT

Veeam Logoby Lasr » Fri Jan 29, 2016 1:26 pm 1 person likes this post

Thank you for the clarification. :wink:

IMHO you should think about twice to use CBT in active fulls, if there is no advantage to do so. Because if there are issues with CBT again, we all get corrupted backups. Active fulls should be the 100% safe option that read the complete disk, whatever CBT says...

I will disable CBT in any case for our monthly fulls.


Regards

lasr
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Re: Monthly backup without CBT

Veeam Logoby Gostev » Sat Jan 30, 2016 8:04 pm

There's a huge advantage of using CBT in active fulls, as this allows us not to read TBs of empty disk blocks, which makes backups finish quicker and reduces the load on the production storage. That said, this is something that we can easily make optional, thus moving the responsibility "to think twice" to users ;)
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Re: Monthly backup without CBT

Veeam Logoby jamerson » Sun Jan 31, 2016 2:01 pm

I wouldn't mind my backups would take long to be snapped if I am sure it not corrupted.
using CBT lately is not safe ,we had to reset the CBT 3 times in a month time.
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Re: Monthly backup without CBT

Veeam Logoby Gostev » Sun Jan 31, 2016 7:00 pm

jamerson wrote:I wouldn't mind my backups would take long to be snapped if I am sure it not corrupted

Except that you cannot be sure your backups are not corrupted until you tested them. Do you realize that in the bigger picture, over the past 7 years of CBT existence, just a few percent of failed recoveries could be attributed to CBT bugs?
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Re: Monthly backup without CBT

Veeam Logoby jamerson » Sun Jan 31, 2016 8:54 pm

agree with you.
creating a backup sure is the solution on this matter.
if we have a backup sure and the test will past, means the backups files are ok.
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