Hi!
Am Mo., 28. Okt. 2019 um 16:14 Uhr schrieb Larkin Lowrey
<llowrey@xxxxxxxxxxxxxxxxx>:
> Reverting to 5.2.18 didn't make a difference not did moving forward to
> 5.3.7.
>
> I noticed that on each reboot the point where it got stuck changed. It
> had been stuck at 14.3MiB dirty then a couple of reboots later it was
> down to 10.7MiB. For example...
>
> On reboot, the dirty was 42.9MiB and proceeded to shrink until it got
> stuck at 10.7MiB. I then rebooted and it was 44.9MiB and shrank to
> 10.0MiB. I rebooted again, and got unlucky, it started at 45.4MiB and
> got stuck at 10.3MiB (an increase from the prior run). I assume that
> mounting and unmounting the fs does generate some small amount of writes
> which may explain the differences.
I'm not sure if I'm seeing the same issue but I'm seeing a similar effect.
Could you try two different settings independently from each other,
and see if it changes behavior? These settings can be applied without
reboot but you may confirm it across reboots (which would need a udev
rule):
You could try setting `writeback_rate_minimum` to a higher value, i.e.
set it to 8192 to let it write 4 MB/s at minimum (it's counted in
sectors).
You could try setting `writeback_percent` to a lower value, i.e. set
it to 0 to aggressively write back all data instead of keeping some
dirty amount around (it's a percent value).
Chances are that it's simply not writing back data fast enough. But
then, there's some other process generating the writes for you, not
bcache itself.
PS: udev rule:
# /etc/udev/rules.d/99-bcache-settings.conf
# Just remove the comment here:
#ACTION=="add|change", KERNEL=="bcache*",
ATTR{bcache/writeback_rate_minimum}="8192"
# or here:
#ACTION=="add|change", KERNEL=="bcache*", ATTR{bcache/writeback_percent}="0"
Regards,
Kai
