Anyone can me explain why the IO pressure stall always display average 0.1% on ZFS on 4x NVMe, but LVM on hardware raid with SSD usually display zero for all time, except rare bursts when VMs is cloning?
IO Pressure Stall
- Thread starter Andrii.B
- Start date
Perhaps because ZFS does write much more often than LVM.
That graph shows an average below 0.15 percent. Do you feel that's a problem?
I don't feel it, of course. But it's strange, because it's there is less writes on ZFS and iostat show the following:
- LVM: AVG 1000 r/s, 25 MB/s, 2 %rrqm, 0.4 r_await, 500 w/s, 7 MB/s, 2 %wrqm, 0.05 w_await, 10 %util
- ZFS: AVG 100 r/s, 1.2 MB/s, 0 %rrqm, 0.1 r_await, 150 w/s, 7 MB/s, 0 %wrqm, 0.2 w_await, 2 %util