VCB Performance consideration

[bodani]

Hi everibody,

I have install a laboratory to test VCB backup, We used ESX 3.5 and VCB 1.5 over a SAN . The backup is working but we have encontered an unexpected situation. We used Windows 2003 virtual machines, when we delete files inside the VM and doing a backup again, the same amount of data is taken. We found is because when the files are deleted the data is always there and taken by VCB. We utilised shrink and the problem was solved, the amount of data was reduced, but the duration of the backup was the same than the initial amount of data. Do you know why?

The duration of the backup was critical for us.

[dconvery]

The Full-VM level of a VCB backup will make a copy of the entire VMDK file, which represents the VM's disk. The only thing I have seen is to defrag and shrink the disk. This method is still only going to shrink a little bit of the file. Copy throughput is only going to be about 1GB / Minute. This seems to be a limitation of Windows when copying from a CMD prompt.

You may want to look at something that does data de-dupe before the backup process or at a third party VCB integrated backup tool.

Dave

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