Io performance issue, suspect cgroup

hi,

We have issue with recent servers that have 50% of iops on same hardware than before. We done quite a lot of tests and the only difference we can find is cgroupv2 vs cgroupv1.

We’d like to test further but i cannot find any way to force lxd (or linux) in cgroupv1.
We use ubuntu22.04 as host. Is there any way to force this so we can rule it out ?

best regards,
Ghislain.

to reply to myself linux kernel parameters

systemd.unified_cgroup_hierarchy=false

but it is deprecated, it works still in ubuntu 22.04

test this night for the io issue :slight_smile:

best regards,
Ghislain.

1 Like

It’s good that you’ve found the way to switch to cgroup1 so I’ve marked it as the solution. I’m however curious to hear back from your testing results. Thanks!

well, my hopes to solve this is down again, the reboot allowed cgroupv1 to be mounted but this does not solved the issue. At least its not a cgroupv2 issue !

Thats is particular the system test is doing a simple php readfile loop more than 2 times slower than other similar machines. it should be a memory read test with file function as it should be in the cache.

well now i am at a loss :slight_smile: so not the cgroupv2 !

best regards,
Ghislain.