Why are digests calculated when last replication job failed?

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Why are digests calculated when last replication job failed?

Veeam Logoby mcz » Wed May 03, 2017 7:28 am

I'm wondering why veeam calculates digests if the last replication pass wasn't successful. AFAIK veeam creates helper snapshots during replication and if an error occurs or the job is being aborted, the vm will be reverted to the "base" snapshot and the helper snapshot will be removed. That means that you do not have a curruption within your disks.

The second thing I know is that CBT can only be used "from snapshot to snapshot" but where is the difference between replication and backup? I mean if you abort a backup job and start it again, CBT will still be used allthough the last backup job wasn't successful. Why can the same behaviour not be transferred to a replication job?

Tnx!
mcz
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Re: Why are digests calculated when last replication job fai

Veeam Logoby DGrinev » Fri May 05, 2017 11:40 am

Hi Michael,

I discussed your issue with the dev team and they confirmed digests recalculation shouldn't be triggered by replication job fail.
Also, the replication job should use CBT similar to the backup job behavior.

Please, contact our support team for detailed investigation of unexpected digest recalculation. Don't forget to share with us the case ID number.

Thanks!
DGrinev
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Re: Why are digests calculated when last replication job fai

Veeam Logoby mcz » Mon May 08, 2017 12:17 pm

DGrinev wrote:
I discussed your issue with the dev team and they confirmed digests recalculation shouldn't be triggered by replication job fail.
Also, the replication job should use CBT similar to the backup job behavior.


Thank you Dmitry for your message. Hmm, maybe I'm little bit confused about this... I think there are two different things to consider:

    Calculating digests (e.g. in case of increased disk size of the source vm)
    Reading whole content of source disk (do not use CBT)

I checked it again and the last entry is the case when the job hasn't been successful before. In the history I can see a replication job, which is titled as "Retry 1", which has the following entry within the job details:

Cannot find dirty block information in the previous restore point, CBT will not be used


Why is CBT not used when the job failed before? As I mentioned before, I cannot see a differenct between replication and backup if we are talking about this behaviour.

Thank you, Regards
Michael
mcz
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Re: Why are digests calculated when last replication job fai

Veeam Logoby DGrinev » Wed May 10, 2017 3:02 pm

Hi Michael,

You are right CBT should be used for the replication.
That's why you should take a closer look on the issue with our technical support and share the case ID number here for us to be in touch. Thanks!
DGrinev
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Re: Why are digests calculated when last replication job fai

Veeam Logoby mcz » Mon May 15, 2017 10:32 am

Hi Dmitry,

case #02155842
mcz
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