On Thu, Oct 6, 2022 at 8:37 PM Jaroslav Pulchart
<jaroslav.pulchart@xxxxxxxxxxxx> wrote:
>
> Hello,
>
> I apply the
> echo 0 > /sys/block/vdc/queue/wbt_lat_usec
> at the production servers. I expect it will disable wbt. Could you
> please confirm that my expectation is correct?
>
> The issue is happening once per ~14-30d after some random higher IOps
> (~25-100k) peak so we need to wait....
Next time when it is triggered, please collect blk-mq debugfs log via
the following
command after the hang is triggered
(cd /sys/kernel/debug/block/vdc && find . -type f -exec grep -aH . {} \;)
Also you can try all kinds of settings, such as reducing the
nr_tags/queue_depth to 4 or
smaller(1), for quick reproduction.
~14-30d is too long to verify any change.
Thanks,
