Very slow incremential backups...

[jzemaitis]

One VM in particular runs fast the first time it backs up (50mb/s) then slows to a crawl the next time it's backed up (6-9MB/s). All other VM's seem to run about the same speed as the initial backup. The VM isn't changing. I've actually ran two backups, back to back, and sure enough, the second time the VM is backup it crawls. It's a 160 GB VM so it takes about 5 hours to back up at the speeds I'm getting. I can usually back up 8 VM's in that amount of time.

I do have it down to a science. If I create a new backup job, the server backs up fast. If I kick that same job off again (even just minutes after the first completes) it's just too slow!

There is nothing special about this VM. It's a P2V VM running File Maker Pro and there is SQL on it. I have 10 other SQL servers that are much busier and theres no problem there. I'm using VMtools not Vss for everything.

[Gostev]

Very interesting problem. Are you backing up this VM to the same location as all other backup jobs not having this issue are using? Also, can you send us log file for your test job, so that we can compare full and incremental runs and see what is taking the time. Thank you.