ZFS causing hight load on CPU

[marshy]

Hey!

So I'm having some issues with ZFS.

I have kinda plenty of ram (64GB), but less than half in use. ARC is limited to 16GB.

Ryzen 3900, with 12/24 cores/threads.

ZFS pool in RAID 0, with 2 NVMe Disks (Gen4), so plenty of speed.
Some modifications were made like:

1. sync=disabled
2. compression=off
3. xattr=sa
4. ashift=12
5. atime=off
6. recordsize=1M

In standard load


When I'm actively using ZFS pool (the load is abnormal)


VM uses
VirtIO SCSI single as SCSI controoler
No cache
SSD emulation
IO Thread enabled
Asycn io: threads


By what it might be caused? Is there a fix for this as kinda don't wanna face such a load every time when I read/write to disk.


zfs-2.1.7-pve3
zfs-kmod-2.1.7-pve3
Kernel proxmox 6.1.2-1-pve

 

[Dunuin]

I don't see the point using ZFS in your case. ZFS sacrifices a lot of resources and performance for additional reliability and data integrity. You disabled sync writes and you are not using any redundacy, so you clearly don't care about your data and you just want best performance, no matter of the costs.
I then would use some HW raid with caching or at least a mdadm software raid with way less overhead instead of ZFS.