Increased IO Delay radically, how to reduce?


Renowned Member
Jan 4, 2014
Good day.
3 month ago average IO Delay increased dramatically, about 10 or 15 times. Nothing radically changed in VMs. Hypervisor hardware also the same. I have 17 VM running: (10 with Windows 7,10, Server 2012) and (7 with Linux Ubuntu 18.04).
There are 3 disks also:
all VMs on nvme0n1 (m.2 ssd)
sda - only backups (sata hdd)
sdb - PVE + swap (sata ssd)
Here is screenshot with typical server load (avarage IO Delay about 10%)
Free memory about 40%. Average CPU usage about 20% ....
Any idea?
Thanks, I saw this post. I do some modifications in sysctl.conf and reboot, but nothing changed:
View attachment 10051

_ratio parameters depend on total RAM. Thus it's recommended to use _bytes instead

one more thing to be clarified. Could you print the output of "zpool status" command (there is l2arc_feed process on one of your screenshots)


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