Re: Raid5 device hangs in active state

I did another sysrq dump and have attached the output.

Again, 'iostat -dx 1' showed 100% utilization on the LVM which uses
/dev/md0 as a pv and /sys/block/md0/md/stripe_cache_active was 29 and
that value did not change. There were no error messages in
/var/log/messages or 'dmesg'.

My suspicions lie with md0 since the stripe_cache_active value remains
at a fixed non-zero value even though all disks are (or appear to be)
idle. Should I be looking elsewhere? This hardware did not exhibit this
problem before "upgrading" from Fedora 15 to Fedora 16.

Thank you,

--Larkin

On 1/8/2012 6:26 PM, NeilBrown wrote:

On Sun, 08 Jan 2012 16:03:10 -0600 Larkin Lowrey

[off-list ref]

wrote:

quoted

Suggestions?

# echo t > /proc/sysrq-trigger

and capture that messages that go to 'dmesg'. Post them.

Hopefully your message ring buffer is big enough to collect the entire
output. If it isn't you might need to boot with
log_buf_len=1M
or similar.

That should show what process is blocking on what.

NeilBrown