Windows disk compression & Veeam

[RMullis]

I have noticed as Veeam backs up one of our file servers and when it hits the second drive it looks like it is performing full backup every day. I have it set to use CBT and it says it is. I checked the size and number of files that change on a daily basis and it is nowhere near the size of the backups. I then noticed the previous admin had configured most of the root folders with Windows disk compression. Could this be the cause of what I am experiencing? If so I will gladly give up the 270GB of disk space needed to decompress if it will help with this.

Thanks,
Rick

[chrisdearden]

If there is a regular routine which is touching or shuffling the files around , it could create a large number of changed blocks , which of course we would have to scan and potentially back up. I have seen this happen with schedule shadow copies too.

[RMullis]

So the compression is not that big of a deal but maybe look for defrag?

[chrisdearden]

I guess when a compress file is access, it is extracted , then recompressed which woudl cause block churn. otherwise a file would be compressed on write to the volume ? so you have to look not only at the files written , but the files read ?

[veremin]

It also stands to reason to check whether there are some side activities that might affect changed block rate, such as defragmentation or antivirus. Thanks.