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Re: Disk spin down

To: Dave Chinner <david@xxxxxxxxxxxxx>
Subject: Re: Disk spin down
From: Andy Bennett <andyjpb@xxxxxxxxxxxxxx>
Date: Sun, 12 Feb 2012 21:28:32 +0000
Cc: xfs@xxxxxxxxxxx
In-reply-to: <4F382BDF.3070901@xxxxxxxxxxxxxx>
References: <4F3803B1.1090205@xxxxxxxxxxxxxx> <20120212200647.GI12836@dastard> <4F382BDF.3070901@xxxxxxxxxxxxxx>
User-agent: Mozilla-Thunderbird 2.0.0.22 (X11/20090707)
Hi,

>> Seems to me that something is still dirtying an inode regularly.
>>
>> Perhaps you need to look at the XFS and writeback event traces to
>> find out what process is dirtying the inode. trace-cmd is your
>> friend...
> 
> Something like this?
> 
> -----
> echo 1 > /sys/kernel/debug/tracing/events/xfs/enable
> 
> echo 0 > /sys/kernel/debug/tracing/events/xfs/enable
> 
> more /sys/kernel/debug/tracing/trace
> -----
> 
> 
> I tried recreating the situation of the last 2 days (clean boot, stopped
> services) and it's currently quiescing nicely. :-(
> 
> I'll keep an eye on it and try to catch it in the act but every time I
> turn the tracing on the HDD light stays firmly off. :-(

There is more interesting news already.

I had used 'hdparm -S 120' to set the spindown_timeout to 10 minutes. It
appears that that was sticking through a cold boot. Setting that back to
its previous value of 1 (5 seconds) makes the disk constantly spin up
and down when I suspect it is idle.

I've caught a trace over the course of a few spinup/downs and attached
it (gzipped as it's 208K unpacked).

When the spindown_timeout was set to 10 minutes I managed to run the
trace for a minute without logging anything. When the spindown_timeout
is 5 seconds much more is logged.





Regards,
@ndy

-- 
andyjpb@xxxxxxxxxxxxxx
http://www.ashurst.eu.org/
0x7EBA75FF

Attachment: trace.gz
Description: application/gzip

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