Move VHDX between zvols in different pools slow

[fabioteixei]

Ok, this one it's really strange and I don't know what it's the problem.

I have an pool, it's a temporary one with only one disk, an Seagate HDD of 2TB. Not sure the model. Nothing special really but not total garbage as well, can get read speeds of 250MBps (or 2Gbps of network traffic) over iSCSI with no problem.

Now I want to move the VHDs stored there to the final location. An zvol on a pool of 3 8TB WD Red disks.

I'm using the move storage option in my Hyper-V Host but the most speed that I can achieve it's something like 50MBps (or 200Mbps of network traffic).

No CPU bottleneck on Truenas or Hyper-V Host. Lots of available memory on Hyper-V as well. Not as much in Truenas, only 48G.

My network settings are two 1gbps NICs (Broadcom Netxtreme II) dedicated to iSCSI in both hosts (Truenas and Hyper-V) with MPIO configured and jumbo frames as well.

Like I said, I have no problem to get to the 2gbps bottleneck of my network with other type of workload, but moving the VHDs it's a pain in the ***, caped at 10%.

Anyone has any idea what it could be?

 

[fabioteixei]

Just an update. All the tests I done with Crystal Disk Mark are fine but when I copy an VHD file from Truenas via iSCSI to the local disk I don't get to 300mbps.

It's really strange.

 

[fabioteixei]

Forget that. The problem it's really the temporary disk. It caps the read speeds to 40MBps.

I don't know why yet but it really doesn't matter. I will use robocopy to copy the VHDs to the new and final zvol.

It will take a while but seems that I don't have any options.