[Lustre-discuss] slow direct_io , slow journal .. in OST log

[Lex]

There was a problem with our raid controller this morning, raid array was
degraded ( I reinstalled the hard drive and its state was *rebuilding* right
after that )  and from messages log, i saw many warnings like this:

*Jan 26 13:59:13 OST6 kernel: Lustre:
9589:0:(filter.c:1363:filter_parent_lock()) lustre-OST0006: slow parent lock
49s
Jan 26 13:59:13 OST6 kernel: Lustre:
9589:0:(filter.c:1363:filter_parent_lock()) Skipped 10 previous similar
messages
Jan 26 13:59:13 OST6 kernel: Lustre:
9638:0:(filter_io.c:398:filter_preprw_read()) lustre-OST0006: slow
preprw_read setup 34s*

I have never seen *slow parent lock *or *preprw-read  *before. Maybe
everything is going down fast and severely, Do all you guys have any ideas
for my situation ?

Just guess, i think it was impacted by performance decreasing issue during
rebuild raid array.

Best regards

On Tue, Jan 26, 2010 at 9:05 AM, Lex <lexluthor87 at gmail.com> wrote:

>
>
> On Tue, Jan 26, 2010 at 12:07 AM, Mark Hahn <hahn at mcmaster.ca> wrote:
>
>>  Sorry Erik if i'm rising such a "bad" question, could u tell me more
>>> about
>>> OST journal device ? I even don't know what it is as well as haven't seen
>>> it
>>> before, in the lustre manual.
>>>
>>
>> an OST is an ext3-ish filesystem associated with some OST server
>> processes.
>> since it's basically ext3, the properties of ext3 apply, including the use
>> of a journal, and the ability to use an "external" journal device.
>>
>
> I think we don't have any separate or external journal device like you
> said. So could anyone tell me exactly what stuff make the warning about slow
> xxx in our OST logs like i described above is ? Is there any role of lustre
> in this situation ? And how? What is the relationship with journal device
> and my problem ?
>
> Best regards
>
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