From: "Bryn M. Reeves" <bmr@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: Bart Kus <me@bartk.us>
Subject: Re: [linux-lvm] Tracing IO requests?
Date: Thu, 03 Mar 2011 10:29:33 +0000 [thread overview]
Message-ID: <4D6F6D8D.6010001@redhat.com> (raw)
In-Reply-To: <4D6EA3EF.1070401@bartk.us>
On 03/02/2011 08:09 PM, Bart Kus wrote:
> Hello,
>
> I have the following setup:
>
> md_RAID6(10x2TB) -> LVM2 -> cryptsetup -> XFS
>
> When copying data onto the target XFS, I notice a large number of READs
> occurring on the physical hard drives. Is there any way of monitoring
> what might be causing these read ops?
The blktrace command is extremely useful for this kind of I/O tracing. I've used
it numerous times to figure out where I/O is originating and also how it's
making its way through layers of stacked devices.
There's a conference talk overview here from a few years ago:
http://www.gelato.org/pdf/apr2006/gelato_ICE06apr_blktrace_brunelle_hp.pdf
And also a user's guide:
http://www.cse.unsw.edu.au/~aaronc/iosched/doc/blktrace.html
http://pdfedit.petricek.net/bt/file_download.php?file_id=17&type=bug
Regards,
Bryn.
prev parent reply other threads:[~2011-03-03 10:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-02 20:09 [linux-lvm] Tracing IO requests? Bart Kus
2011-03-02 20:13 ` Jonathan Tripathy
2011-03-02 22:19 ` Bart Kus
2011-03-02 23:00 ` Dave Sullivan
2011-03-02 23:44 ` Ray Morris
2011-03-03 0:25 ` Bart Kus
2011-03-07 16:02 ` Frank Ch. Eigler
2011-03-07 18:06 ` Wendy Cheng
2011-03-03 10:29 ` Bryn M. Reeves [this message]
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