Large VM restore Speed (Advice Needed)

[BenB1978]

Hi,
I'm currently restoring a series of vmware machines from veeam backups (ver 7.0.0.771), to a DR site (for testing purposes), and am running into a potential performance issue with a large file server vm.

When restoring smaller vm's (i.e. 100-500GB in size), I am seeing no issues and the restore is running at roughly the fastest speed the underlying storage will allow (approximately 35MB\s). When restore the large file server (4.7 Terabytes), I am seeing this speed drop down to only 406KB\s. The veeam proxy being used for the restore is using hotadd and I've assigned 4 vCPU's and 32GB or RAM as initially I thought it may be down to memory resources on the proxy and a need to decompress the large veeam backup file, but this doesn't seem to have helped.

Looking at the storage level, the target and the host appear to be doing very little (I would expect it to be reading from the source quickly, even if writing to the target was slow), so it would appear that the bottleneck is veeam. As stated above, with smaller vm's I don't see this issue, and they are being restored using the same proxy and target and source locations, but something is obviously different when it comes to large vm's. Are there any obvious changes I could look at before I raise a support ticket?

Thanks in advance

[foggy]

Ben, generally, VMFS is known to be not very efficient in writing large files (due to how metadata is managed). I recommend reviewing the following existing threads, probably will give you some thoughts:

Restore speed entire VM?
slow restore speed veeam7 1GB / minute
Slow Restore Speed - 27MB/s - Tips/Ideas?

[BenB1978]

Thanks for the tip foggy...After further investigation, I think the issue in this case may be due to corruption within the .vbk file I'm restoring from, but if that isn't the case I'll revisit the vmfs possibility you mention. Many thanks for your assistance.

[foggy]

If none of the tips given in the referred threads help, feel free to open a case with our technical support for closer look at your environment.