From: Vladislav Bogdanov <bubble@hoster-ok.com>
To: linux-lvm@redhat.com
Subject: Re: [linux-lvm] cLVM commands often taking a long time to execute
Date: Tue, 15 Nov 2011 10:58:18 +0300 [thread overview]
Message-ID: <4EC21B9A.4080702@hoster-ok.com> (raw)
In-Reply-To: <3D44B3DCE57399449CC1391C2AD6EC4C16EB33A8@ORSMSX101.amr.corp.intel.com>
10.11.2011 19:16, Riches Jr, Robert M wrote:
> Thank you, Vladislav, for the suggestion. That could potentially
> help in cases where the nodes are CPU-bound, likely independent of
> whether they are I/O-bound.
Except filtering unneeded block devices. This greatly helps in IO-bound
setups.
>
> Thanks,
>
> Robert Riches
>
> -----Original Message----- From: linux-lvm-bounces@redhat.com
> [mailto:linux-lvm-bounces@redhat.com] On Behalf Of Vladislav
> Bogdanov Sent: Thursday, November 10, 2011 1:06 AM To:
> linux-lvm@redhat.com Subject: Re: [linux-lvm] cLVM commands often
> taking a long time to execute
>
> 09.11.2011 03:06, Riches Jr, Robert M wrote:
>> I'm running into some odd behavior from clustered LVM commands on a
>> 3-node pacemaker-based cluster. When other processes on the nodes
>> are doing somewhat heavy sequential I/O traffic, LVM commands such
>> as lvs, pvs, vgs, lvdisplay, pvdisplay, and vgdisplay have widely
>> variable, often very long execution times. The same LVM command
>> done repetitively will have execution times varying from less than
>> a second to 10-15 seconds, more rarely up to around 60 seconds.
>> Other read-heavy commands such as find, wc, and sum have much less
>> variability and much shorter tails in the distribution of their
>> execution times.
>>
>> Is it known what causes the cLVM commands to be so slow at times?
>>
>> Perchance, are there known ways to get cLVM commands to be less
>> slow?
>
> I use chrt -r 99 for them. And I also run clvmd the same way. But
> this is much more about CPU load then IO load. Also, please make sure
> that you correctly filter unneeded block devices from being
> PV-suspects (filter clause in lvm.conf).
>
> Best, Vladislav
>
> _______________________________________________ linux-lvm mailing
> list linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO
> at http://tldp.org/HOWTO/LVM-HOWTO/
>
> _______________________________________________ linux-lvm mailing
> list linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO
> at http://tldp.org/HOWTO/LVM-HOWTO/
prev parent reply other threads:[~2011-11-15 7:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-09 0:06 [linux-lvm] cLVM commands often taking a long time to execute Riches Jr, Robert M
2011-11-10 9:05 ` Vladislav Bogdanov
2011-11-10 16:16 ` Riches Jr, Robert M
2011-11-15 7:58 ` Vladislav Bogdanov [this message]
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