From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id l8LHQOF0023402 for ; Fri, 21 Sep 2007 13:26:24 -0400 Received: from web33614.mail.mud.yahoo.com (web33614.mail.mud.yahoo.com [68.142.199.246]) by mx1.redhat.com (8.13.1/8.13.1) with SMTP id l8LHQHEs007463 for ; Fri, 21 Sep 2007 13:26:17 -0400 Date: Fri, 21 Sep 2007 10:26:11 -0700 (PDT) From: Sagar Borikar Subject: Re: [linux-lvm] exception when snapshot size is less than the volume size In-Reply-To: <46F2D78F.5020705@redhat.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1328842134-1190395571=:71432" Content-Transfer-Encoding: 8bit Message-ID: <440173.71432.qm@web33614.mail.mud.yahoo.com> Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: To: LVM general discussion and development --0-1328842134-1190395571=:71432 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Hi Milan, Thanks a lot! It worked very nice! Cheers Sagar Milan Broz wrote: Hi, this is an old snapshot bug, already fixed in all recent kernels - see http://bugzilla.kernel.org/show_bug.cgi?id=7040 Plese could you try to apply patch mentioned in this bugzilla ? also here http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.18.y.git;a=commitdiff;h=2b64e22fdbc35b4a0e7c1cbda590daaced401c35;hp=6e28fa8b0390dcbb883994f3c634c1f56fe4f93a (or simply use latest stable 2.6.18.8 kernel) Milan -- mbroz@redhat.com Sagar Borikar wrote: > In my NAS box, I observed strange thing yesterday. I had the snapshot > size (32MB) less than volume size was (10 GB) You can say I was trying > to do failure analysis of my box. The LVM HOwto for snapshot says > " > ** > > > If the snapshot logical volume becomes full it will be dropped (become > unusable) so it is vitally important to allocate enough space. The > amount of space necessary is dependent on the usage of the snapshot, so > there is no set recipe to follow for this. If the snapshot size equals > the origin size, it will never overflow. > > " > But my box was crashed in this scenario. > Was wondering why didn't it disable the snapshots. > The underlying processor is MIPS and linux kernel version is 2.6.18. > After delving little bit in the sources I found that break is occurring > while blowing away the snapshot facility -- so it`s not surprising that > snapshots do not work anymore. Just before the error, > kcopyd_client_destroy is called -- so that`s it for kcopyd jobs -- hence > snapshots. The snapshot faciltiy is gone at that point, with or without > the BUG_ON. The error actually occurs while freeing the exception tables > in the slab cache. > > Any pointers if this has been resolved? > I am working with lvm version 2.02.28. and device mapper version 1.02.22 _______________________________________________ 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/ --------------------------------- Shape Yahoo! in your own image. Join our Network Research Panel today! --0-1328842134-1190395571=:71432 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit
Hi Milan,
 
Thanks a lot!
It worked very nice!
 
Cheers
Sagar

Milan Broz <mbroz@redhat.com> wrote:
Hi,

this is an old snapshot bug, already fixed in all
recent kernels - see http://bugzilla.kernel.org/show_bug.cgi?id=7040

Plese could you try to apply patch mentioned in this bugzilla ?
also here
http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.18.y.git;a=commitdiff;h=2b64e22fdbc35b4a0e7c1cbda590daaced401c35;hp=6e28fa8b0390dcbb883994f3c634c1f56fe4f93a

(or simply use latest stable 2.6.18.8 kernel)

Milan
--
mbroz@redhat.com

Sagar Borikar wrote:
> In my NAS box, I observed strange thing yesterday. I had the snapshot
> size (32MB) less than volume size was (10 GB) You can say I was trying
> to do failure analysis of my box. The LVM HOwto for snapshot says
> "
> **
>
>
> If the snapshot logical volume becomes full it will be dropped (become
> unusable) so it is vitally important to allocate enough space. The
> amount of space necessary is dependent on the usage of the snapshot, so
> there is no set recipe to follow for this. If the snapshot size equals
> the origin size, it will never overflow.
>
> "
> But my box was crashed in this scenario.
> Was wondering why didn't it disable the snapshots.
> The underlying processor is MIPS and linux kernel version is 2.6.18.
> After delving little bit in the sources I found that break is occurring
> while blowing away the snapshot facility -- so it`s not surprising that
> snapshots do not work anymore. Just before the error,
> kcopyd_client_destroy is called -- so that`s it for kcopyd jobs -- hence
> snapshots. The snapshot faciltiy is gone at that point, with or without
> the BUG_ON. The error actually occurs while freeing the exception tables
> in the slab cache.
>
> Any pointers if this has been resolved?
> I am working with lvm version 2.02.28. and device mapper version 1.02.22

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