No, I was in doubt that it could be a serial task.

I can confirm the parallelism, as I tried with 2 VMS, both with 3 disks: 20Gb+20Gb+90Gb the first VM1 and 20Gb+20Gb+80Gb the second one VM2.

The source storage domain is based on iSCSI Equallogic with 10Gbit/s connection.

The export domain is a vSphere VM (on 10Gb/s adapter) connected through the ovirtmgmt channel (that is based on 10Gb/s adapters in LACP)

Going one by one I got

Starting export Vm VM1 to xfer 11/4/21 12:14:49 PM
Vm VM1 was exported successfully to xfer 11/4/21 12:21:54 PM

--> total 7' 5"

Starting export Vm VM2 to xfer 11/4/21 12:25:23 PM
Vm VM2 was exported successfully to xfer 11/4/21 12:32:19 PM

--> total 6' 56"

Going then in parallel (delay of 7 seconds, not using the method of multi-select and export):

Starting export Vm VM1 to xfer 11/4/21 3:15:29 PM
Starting export Vm VM2 to xfer 11/4/21 3:15:36 PM
Vm VM2 was exported successfully to xfer 11/4/21 3:26:32 PM
Vm VM1 was exported successfully to xfer 11/4/21 3:26:46 PM

---> total 11' 17"

So I got about a 20% gain.

Next week I have to move some VMs with 900Gb of storage each, so I can get optimizations going in parallel

Thanks,

Gianluca