From mboxrd@z Thu Jan 1 00:00:00 1970 From: Syed Mushtaq Subject: Re: LVM performance problems with large number of VGs Date: Fri, 1 Apr 2016 11:53:16 -0400 Message-ID: References: <20160401152210.GL27636@citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8417702309234002974==" Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1am1Nv-0006cx-1G for xen-devel@lists.xenproject.org; Fri, 01 Apr 2016 15:53:19 +0000 Received: by mail-qg0-f41.google.com with SMTP id n34so91716100qge.1 for ; Fri, 01 Apr 2016 08:53:17 -0700 (PDT) In-Reply-To: <20160401152210.GL27636@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Wei Liu Cc: "Tutkowski, Mike" , Will Stevens , Marc Vaillancourt , Pierre-Luc Dion , xen-devel@lists.xenproject.org, Tim Mackey List-Id: xen-devel@lists.xenproject.org --===============8417702309234002974== Content-Type: multipart/alternative; boundary=001a113a96f88f1e52052f6e6071 --001a113a96f88f1e52052f6e6071 Content-Type: text/plain; charset=UTF-8 I understand that Xenserver has a different channel but I thought of mailing here as it would target a wider audience and I believe the problem that I am facing would also surface itself within upstream Xen as well as Xen also uses LVM as one of its storage options and the problem is very specific to LVM. Thanks, -Syed On Fri, Apr 1, 2016 at 11:22 AM, Wei Liu wrote: > On Fri, Apr 01, 2016 at 10:23:42AM -0400, Syed Mushtaq wrote: > > Hi, > > > > I am testing out a system in which each Guest disk is mapped to a LUN on > a > > backend storage. I am using Xenserver 6.5 for this and creating an SR > with > > a single VDI inside it for each Guest disk. The way it would work is, > from > > an LVM point of view, I would have a Volume Group (VG) for each virtual > > disk and a single logical volume (LV) inside that VG. What I am seeing is > > that creating new volume groups is taking a lot of time. In my test after > > creating about 600 volume groups, it took about 4 seconds to create a new > > one. I have observed this to be a linear trend where the more VGs I add > the > > slower future operations become. Other operations like getting the > logical > > volumes inside a VG have also slowed down (even though there is only 1 LV > > per VG). > > > > I was wondering if anyone here faced a similar problem or had some > > experience in dealing with LVM bottlenecks. > > > > Hi this mailing list is for upstream Xen development. For XenServer > related stuff please go to xenserver.org and look for correct channel > there. > > Wei. > > > Thanks, > > -Syed > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xen.org > > http://lists.xen.org/xen-devel > > --001a113a96f88f1e52052f6e6071 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I understand that Xenserver has a different chan= nel but I thought of mailing here as it would target a wider audience and I= believe the problem that I am facing would also surface itself within upst= ream Xen as well as Xen also uses LVM as one of its storage options and the= problem is very specific to LVM.

Thanks,
-Syed
= =C2=A0

O= n Fri, Apr 1, 2016 at 11:22 AM, Wei Liu <wei.liu2@citrix.com> wrote:
On Fri, Apr 0= 1, 2016 at 10:23:42AM -0400, Syed Mushtaq wrote:
> Hi,
>
> I am testing out a system in which each Guest disk is mapped to a LUN = on a
> backend storage. I am using Xenserver 6.5 for this and creating an SR = with
> a single VDI inside it for each Guest disk. The way it would work is, = from
> an LVM point of view, I would have a Volume Group (VG) for each virtua= l
> disk and a single logical volume (LV) inside that VG. What I am seeing= is
> that creating new volume groups is taking a lot of time. In my test af= ter
> creating about 600 volume groups, it took about 4 seconds to create a = new
> one. I have observed this to be a linear trend where the more VGs I ad= d the
> slower future operations become. Other operations like getting the log= ical
> volumes inside a VG have also slowed down (even though there is only 1= LV
> per VG).
>
> I was wondering if anyone here faced a similar problem or had some
> experience in dealing with LVM bottlenecks.
>

Hi this mailing list is for upstream Xen development. For XenServer<= br> related stuff please go to xenserver.org and look for correct channel
there.

Wei.

> Thanks,
> -Syed

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org=
> http://lists.xen.org/xen-devel


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