High CPU usage when moving VMs/LXCs from/to ZFS pools

Has anybody noticed that whenever you are moving VMs/LXCs around in Proxmox (that’s running ZFS) that you have high CPU usage during the moves?

My Proxmox server has dual Xeon E5-2697A v4 (16-core/32-thread) with 256 GB and I am running a grand total of 36 HDDs (OS: 4x3TB RAID6 on 9341-8i, VM: 8x6TB raidz2, bulk data: 8x12TB raidz2+8x10TB raidz2+8x10TB raidz2).

My current load average is about 101 as I am moving three LXCs over from my LVM pool which lives on the RAID6 pool over to my VM pool (raidz2) and I am wondering if ZFS is the culprit for that.

Has anybody else noticed or experienced this before?

Thanks.

If you fire up top or htop or similar, sort by CPU, and turn on the display of kernel/system activity and threads, what rises to the top?

Stupid question – how do I turn off the display for kernel/system activity and threads?

There are two of each of the follow threads:
z_rd_iss
z_rd_int_{0..6}

At least that’s what’s showing right now.