Re: INFO: task md2_resync:7950 blocked for more than 120 seconds

On Sunday May 4, wyldavolny.cz wrote:
> Hello,
> 
> today i noticed in syslog some strange entries
triggered by checkarray.
> I cannot judge if those are harmless messages or it
means, that something
> bad is happening. So is it bad or just a bug?

Hi,
 your attachment was very large and so the original mail
didn't go out
to the list but went to the moderator instead, and I ended
up with it
(thanks Alasdair!).

The syslog contained lots of things like:

May  4 00:57:02 ss4000 mdadm: RebuildStarted event detected
on md device /dev/md0
May  4 00:57:02 ss4000 kernel: md: delaying data-check of
md1 until md2 has finished (they share one or more physical
units)
May  4 00:57:02 ss4000 kernel: md: delaying data-check of
md2 until md0 has finished (they share one or more physical
units)
May  4 01:20:26 ss4000 kernel: INFO: task md1_resync:7949
blocked for more than 120 seconds.
May  4 01:20:26 ss4000 kernel: "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this
message.
May  4 01:20:26 ss4000 kernel: md1_resync    D c02c01b8    
0  7949      2
May  4 01:20:26 ss4000 kernel: [<c02bff50>]
(schedule+0x0/0x2d4) from [<c0221ed0>]
(md_do_sync+0x1dc/0x950)
May  4 01:20:26 ss4000 kernel: [<c0221cf4>]
(md_do_sync+0x0/0x950) from [<c02237a0>]
(md_thread+0x114/0x130)
May  4 01:20:26 ss4000 kernel: [<c022368c>]
(md_thread+0x0/0x130) from [<c004ea7c>]
(kthread+0x5c/0x94)
May  4 01:20:26 ss4000 kernel: [<c004ea20>]
(kthread+0x0/0x94) from [<c003c3dc>]
(do_exit+0x0/0x328)
May  4 01:20:26 ss4000 kernel:  r6:00000000 r5:00000000
r4:00000000
May  4 01:20:27 ss4000 kernel: no locks held by
md1_resync/7949.
May  4 01:20:27 ss4000 kernel: INFO: task md2_resync:7950
blocked for more than 120 seconds.

suggesting that 'md1_resync' was blocked waiting for disk IO
for 2 minutes
multiple times.

I have heard of another case of this happening when the md
arrays were
built on top of dm logical volumes.

Could you please report exactly what kernel and distro you
are using,
and describe your storage setup (what devices, what LVM, DM,
MD, loop,
crypto, filesystem,.... is being used and how).

NeilBrown

--
dm-devel mailing list
dm-develredhat.com
http
s://www.redhat.com/mailman/listinfo/dm-devel

For multipathd and dm is round-robin the only mode for
multipathing? The
array we have as a newer Hitachi AMS200 and Active/Passive
says the
documentation. 

Using round-robin seems to work fine with it. Have 4 paths
and they are
all sharing 1/4 of the load. 

Are there other options that can be set in
/etc/multipath.conf? I only
know of round-robin. 

Craig  

--
dm-devel mailing list
dm-develredhat.com
http
s://www.redhat.com/mailman/listinfo/dm-devel