[linux-lvm] Cpy%Sync column - high disk activity after reboots

[Mathijs Kwik]

Hi all,

I'm trying lvmcache and it seems to work ok. However, after every
reboot, I notice quite a long period of disk activity. lvs gives me this
output:

% lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
btrfs-spinner bluebook Cwi-aoC--- 582,19g [cache] [btrfs-spinner_corig] 70,11 11,34 82,55

The % gets lower over time and when it reaches 0 the disk activity goes
back to normal.

Is this to be expected/normal?
It seems to me the entire cache is checked as if it wasn't cleanly
closed on shutdown. I'm currently using writethrough and would like to
make sure everything is ok before enabling writeback.

Thanks,
Mathijs

[Zdenek Kabelac]

Post by Mathijs Kwik
Hi all,
I'm trying lvmcache and it seems to work ok. However, after every
reboot, I notice quite a long period of disk activity. lvs gives me this
% lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
btrfs-spinner bluebook Cwi-aoC--- 582,19g [cache] [btrfs-spinner_corig] 70,11 11,34 82,55
The % gets lower over time and when it reaches 0 the disk activity goes
back to normal.
Is this to be expected/normal?
It seems to me the entire cache is checked as if it wasn't cleanly
closed on shutdown. I'm currently using writethrough and would like to
make sure everything is ok before enabling writeback.

Hi

Cache is always flushing it's content to disk - so if you have the 'writeback'
variant and there were some unwritten data which sits only in cache, they are
automatically pushed to origin (cached) device - which is likely your disk
activity.

Zdenek

[Mathijs Kwik]

I'm sorry if I was unclear. But I'm not using writeback mode yet.
The period of disk activity after reboots occurs with writethrough mode.

Post by Zdenek Kabelac
Hi
Cache is always flushing it's content to disk - so if you have the
'writeback' variant and there were some unwritten data which sits only
in cache, they are automatically pushed to origin (cached) device -
which is likely your disk activity.
Zdenek

[Zdenek Kabelac]

Post by Mathijs Kwik
I'm sorry if I was unclear. But I'm not using writeback mode yet.
The period of disk activity after reboots occurs with writethrough mode.

Please attach:

dmsetup table

dmsetup status

dmsetup ls --tree


Zdenek