Re: [linux-lvm] LVM RAID: task mdX_raid1:221 blocked for more than 120 seconds

[Zdenek Kabelac <zkabelac@redhat.com>]

Dne 26. 11. 18 v 12:31 Cesare Leonardi napsal(a):
> Resending, I erroneusly replied only to Zdenek, sorry.
> 
> 
> 
> I can provide details about this, that was filed by me:
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=913119
> 
> It's about a desktop PC, with two SSD (Samsung 850 EVO) on which i build RAID1 
> using LVM.
> # pvs
>  � PV�������� VG� Fmt� Attr PSize��� PFree
>  � /dev/sdb3� vg0 lvm2 a--� <250,00g 15,98g
>  � /dev/sdc3� vg0 lvm2 a--� <250,00g 15,98g
> 
> # lvs
>  � LV��� VG� Attr������ LSize�� Pool Origin Data%� Meta%� Move Log Cpy%Sync 
> Convert
>  � home� vg0 rwi-aor--- 200,00g 100,00
>  � root� vg0 rwi-aor---� 30,00g 100,00
>  � swap0 vg0 rwi-aor---�� 4,00g 100,00
> 
> It's a desktop PC using Debian unstable, so it's rebooted quite often due to 
> frequent updates.

So you should probably start first with running latest available kernel - 4.19.

You also should collect 'dmesg' report

> The freezes happens during normal work, without any resizing or any 
> maintenance on LVM going on. Most of the time I noted the freeze while I was 
> using Thunderbird. But eventually they resolve by themself: I wait minutes and 

Aren't you running out-of-memory ?

Install some CPU/MEM monitoring service and watch out for problems
(AFAIK OOM doesn't really work on my machine - and often  FF + Thunderbird 
combo brings it to the state mouse barely moves and CPU spins in kswapd...)

> I've not noticed any corruption due to these freeze but often they are very 
> long and very impacting. The only reliable workaround found was to reboot with:
> scsi_mod.use_blk_mq=0 dm_mod.use_blk_mq=0

I doubt this have anything in common with this.

Regards

Zdenek