You gave some different details in your other post, but here you mention use of 
GPU pass through.

Any pass through will lose you the live migration ability, but unfortunately 
with GPUs, that's just how it is these days: while those could in theory be 
moved when the GPUs were identical (because their amount of state is limited to 
VRAM size), the support code (and kernel interfaces?) simply does not exist 
today.

In that scenario a pass-through storage device won't lose you anything you 
still have.

But you'll have to remember that PCI pass-through works only at the granularity 
of a whole PCI device. That's fine with (an entire) NVMe, because these combine 
"disks" and "controller", not so fine with individual disks on a SATA or SCSI 
controller. And you certainly can't pass through partitions!

It gets to be really fun with cascaded USB and I haven't really tried 
Thunderbolt either (mostly because I have given up on CentOS8/oVirt 4.4)

But generally the VirtIOSCSI interface imposes so little overhead, it only 
becomes noticeable when you run massive amounts of tiny I/O on NVMe. Play with 
the block sizes and the sync flag on your DD tests to see the differences, I've 
had lots of fun (and some disillusions) with that, but mostly with Gluster 
storage over TCP/IP on Ethernet.

If that's really where your bottlenecks are coming from, you may want to look 
at architecture rather than pass-through.
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