How to determine size of next/current CopySync Transfer

[AdrianHinton]

Hi,

How can you determine the amount of change that will be transferred in a copysync job? For instance, if I have a backup named backup1 and a copysync job named backup1-copy and if the last run of backup1 was a (Full), how can I estimate the amount of data that will be transferred to the target in the next backup1-copy job?

[foggy]

Adrian, this solely depends on the VM guest data change rate and is generally hardly predictable. Backup copy job copies only those blocks that correspond to VM latest state and have changed since its last run. Considering that change rate inside the VM is pretty constant, you can take the size of an average increment created by the backup copy job as an estimate.

[Vitaliy S.]

Also keep in mind that if you're using WAN accelerators, then the amount of transferred data will also depend on the cache size/cache content that you already have from the previous job runs/other jobs.

[AdrianHinton]

Hi Vitaliy, I usually look at the last backup job run. If this says it's transferred 5GB, then the next CopySync job will transfer very close to that amount. But when a Full backup occurs, close to the entire VM size is transferred in the Backup job. So it is when this happens I would like to be able to predict how much data will be transferred in the copy job. I guess what you are saying is there is no way to do this other than guess. I was hoping I could view a file or a log and make a precise calculation.

Thanks for the response.

[foggy]

Yes, you can just perform an estimate based on the previous increments you have. Anyway, backup copy does not need to transfer the entire full backup data, it will copy only those blocks that are new in relation to what is already stored on target.

[AdrianHinton]

Yes, and that's what I was hoping to calculate

Thank you Foggy

[AdrianHinton]

Hi all,

I have been looking more into this and I have found in the logs some better indication on how much data is to be transferred in the Copy job:

"Job progress: '81%', '781,432,913,920' of '957,777,707,008' bytes, object '0' of '1'"

The above data is from C:\ProgramData\Veeam\Backup\CopyJobName.BackupSync.Log

[Andreas Neufert]

There is also our Veeam ONE with Change Rate Estimation report in case you never backed up a VM, this Report is very helpful.