Different compression and deduplication ratio

[adam900331]

Hy!

I have a backup job which has some VM to backup. The backup repository is a Synology NAS. I noticed that the deduplication and the compression rate not equal all backup. Why?

This is incremental backups:
Name Data_size Deduplication Compression
VMs 45,7 GB 1,2x 2,8x
VMs 38,6 Gb 1,1x 2,7x
VMs 109 Gb 1,4x 1,6x
...

Why the deduplication and compression different every day and not equal? What depends on?

Thanks.

[ronnmartin61]

It is 100% dependent on the block-level storage changes that are occurring on the VM's between backups. We have a feature coming in VBR v12 which can compare backup points to a running VM to show filesystem level changes if you're interested in exploring what is changing at the filesystem level. In the interim we have a tool for running filesystem level diffs for Windows workload backups today - https://github.com/VeeamHub/veeam-restore-point-utility (not formally supported by Veeam)