I have been tracing down some issues with slow performance in our virtual environment and Veeam backups. We have seen an issue with high fragmentation at the guest OS level - maybe because we have never run defrag on any of our Windows guests .
I was pointed to the Raxco vSphere edition as a possible solution but am curious if any other Veeam users have experience with this PerfectDisk product? I am hesistant to deploy anything that requires a client in our virtualized environment but it appears that this product will do both the defrage and sDelete functions automatically.....
Anyone use this or a similar product and did you see any appriciable decrease in CBT or in IO load on your storage?
Hi Andrew,
only read about Raxco but never tried it. They claim the have a way to optimize thin disks without inflating it, and it could also be true, what I'm doubtful about is the usual high increase in changed blocks tools like this can create, thus ruining performances of an incremental backup.
I've this tool on my "to test" list, I'm too interested in seeing how it can change backup times touching CBT blocks.
Luca.
Luca Dell'Oca Principal EMEA Cloud Architect @ Veeam Software
Yes, high amounts of file and/or free space fragmentation in a guest can impact performance since it will result in unnecessary SCSI commands (one for each extent) being sent to the hyper-visor. If files and free space are optimized, it results in fewer but larger (and more efficient) I/Os being sent to the hyper-visor - reducing IOPS, reducing queue depth and increasing sequential I/O. However, there are challenges/considerations in a virtual environment - especially when thin provisioning is concerned since you want to try to NOT blow our thin provisioned drives in the process of improving performance.
When virtual awareness is enabled in PerfectDisk vSphere, PD will detect if a guest drive is thin-provisioned and if so will configure defrag settings to be thin-provisioned friendly. It changes the default optimization method to Defrag Only (fewer changes to the drive than a more comprehensive method like Smart Placement or Consolidate Free Space). It also changes it's free space search method from Backwards (looking toward the end of the drive for free space) to Forwards (looks toward the front of the drive for free space). It also will NOT allow optimization if the guest has snapshots.
Even in a non-virtual or non-thin provisioned environment, you can configure PerfectDisk so that it does the above (free space search method, optimization method) in order to minimize cluster changes that could impact CBT and backup sizes.
.