Re: LVM performance problems with large number of VGs

From: Syed Mushtaq <syed1.mushtaq@gmail.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: "Tutkowski, Mike" <Mike.Tutkowski@netapp.com>,
	Will Stevens <wstevens@cloudops.com>,
	Marc Vaillancourt <mvaillancourt@cloudops.com>,
	Pierre-Luc Dion <pdion@cloudops.com>,
	xen-devel@lists.xenproject.org,
	Tim Mackey <Timothy.Mackey@citrix.com>
Subject: Re: LVM performance problems with large number of VGs
Date: Fri, 1 Apr 2016 11:53:16 -0400	[thread overview]
Message-ID: <CADMzvUp_44F94yBZDv0y8xO3b6CEvdz3zHyS5diQ1Urx63a=nA@mail.gmail.com> (raw)
In-Reply-To: <20160401152210.GL27636@citrix.com>

[-- Attachment #1.1: Type: text/plain, Size: 1739 bytes --]

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 <wei.liu2@citrix.com> 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
>
>

[-- Attachment #1.2: Type: text/html, Size: 2447 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

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