RE: [linux-lvm] 'snapshot' target still experimental :-(

From: Ming Zhang <mingz@ele.uri.edu>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: RE: [linux-lvm] 'snapshot' target still experimental :-(
Date: Wed, 01 Feb 2006 15:54:36 -0500	[thread overview]
Message-ID: <1138827276.4762.88.camel@localhost.localdomain> (raw)
In-Reply-To: <0456A130F613AD459887FF012652963F33ED0C@mail7.amherst.edu>

i can confirm this. iet runs well with heavy io until you create many
snapshots. lvresize will be slow as well, though not hang. i think that
is because the outstanding bio? not quite since i faced that several
months ago.

ps, not lvm related, but if u stop iet for 5 seconds. i guess iscsi ini
will be unhappy? :P we can discuss in iet list.

ming

On Wed, 2006-02-01 at 13:39 -0500, Steffen Plotner wrote:
> Hi,
> 
> I apologize for looking up your machine. I have reported this problem
> sometime ago in November of last year.  
> 
> https://www.redhat.com/archives/linux-lvm/2005-November/msg00044.html
> 
> We currently deployed an iscsi-target (from sourceforge) server on FC4
> which functions well, until we utilize snapshots. The way I currently
> remove snapshots is to stop the iscsi-target daemon for 5 seconds, to
> let everything settle, then remove the snap, the restart the
> iscsi-target and all is ok (of course this is not how I would like to do
> things.. :).
> 
> I have tried several patches dm and lvm in late December and they did
> not help. I have specifics at my house. I will email those later on.
> Thank you for responding to this issue.
> 
> Steffen
> 
> -----Original Message-----
> From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Alasdair G Kergon
> Sent: Wednesday, February 01, 2006 1:31 PM
> To: LVM general discussion and development
> Subject: Re: [linux-lvm] 'snapshot' target still experimental :-(
> 
> On Wed, Feb 01, 2006 at 01:07:20PM -0500, Steffen Plotner wrote:
> > cd to a directory on an lv that has an active snapshot dd if=/dev/zero
> 
> > of=test bs=1M count=10000
>  
> > And see how hard it is to remove a live active snapshot. 
> 
> Strange - I don't recall anyone reporting that problem before.
> 
> I've just tried it here and the machine locked up:-(
> 
> Alasdair
> --
> agk@redhat.com
> 
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