Date: Thu, 21 Jun 2007 13:10:34 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Cristian KLEIN <cristi@net.utcluj.ro> Cc: freebsd-fs@freebsd.org, Espen Skoglund <esk@ira.uka.de> Subject: Re: Snapshot usage guidelines (to avoid stability issues) Message-ID: <20070621101034.GB2268@deviant.kiev.zoral.com.ua> In-Reply-To: <467A45B8.3070303@net.utcluj.ro> References: <18041.21810.297355.202403@gargle.gargle.HOWL> <20070620165746.GX2268@deviant.kiev.zoral.com.ua> <4679AE0C.5040306@net.utcluj.ro> <20070621090333.GA2268@deviant.kiev.zoral.com.ua> <467A45B8.3070303@net.utcluj.ro>
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--2tb6s275ZjQu9Nb2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 21, 2007 at 12:32:40PM +0300, Cristian KLEIN wrote: > Kostik Belousov wrote: > > On Thu, Jun 21, 2007 at 01:45:32AM +0300, Cristian KLEIN wrote: > >> Kostik Belousov wrote: > >>> On Wed, Jun 20, 2007 at 06:26:26PM +0200, Espen Skoglund wrote: > >>>> Hi, > >>>> > >>>> A couple of days ago I decided to start using snapshots on my system. > >>>> Knowing that the functionality has been available for quite some time > >>>> now I (apparently wrongly) assumed that it was ready for production > >>>> use. My bad. > >>>> > >>>> My system, a 6-STABLE from week and a half ago, uses two 250GB > >>>> gstriped disks and has about 4-5 snapshots on one 215GB UFS partiton. > >>>> This morning I learned that things had gone terribly wrong during so= me > >>>> nightly cronjobs, hanging the whole system. Suspecting that snapsho= ts > >>>> were the culprit I soon learned after some investigation that the > >>>> snapshot functionality wasn't nearly as stable as I had hoped for. > >>>> > >>>> Looking at PRs and mailing lists there seems to be mainly two > >>>> outstanding stability issues with snapshots: a) snapshotted fs runni= ng > >>>> full, and b) deleting large amount of files on an fs with multiple > >>>> snapshots. The former issue, while certainly annoying, one could be > >>>> able to work around. The latter issue, on the other hand, seems more > >>>> like a definite show stopper. > >>>> > >>>> Am I right in inferring that the two above cases are main issues with > >>>> snaphots at this time, or are there other known gotchas that I have = to > >>>> look out for. > >>> About the issue b). Are you system sources before or after 2007-06-11 > >>> 10:53:48 UTC ? Or simply show me the version of sys/ufs/ffs/ffs_snaps= hot.c. > >>> > >>> If it is less then 1.103.2.24, see developers handbook for instructio= n on > >>> reporting deadlocks. > >>> > >> Do you think that 1.103.2.24 might solve this > >> http://lists.freebsd.org/pipermail/freebsd-fs/2007-May/003161.html ? > > I very much doubt it. AFAIR, I asked at least ddb backtrace for the cra= sh, > > and you did not answered. >=20 > I'm really sorry, but I wasn't able to reproduce the problem on another > system. I tried taking / deleting many snapshots while running bonnie++, > but the panic would not occur. >=20 > I have 1,7mil inodes (4% utilization) on the server where the crash > occured. Might this be a prerequisite of the panic? It may be related to inode/cyl groups density ratio. --2tb6s275ZjQu9Nb2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFGek6ZC3+MBN1Mb4gRAstNAKC5IbY1VwR4Jw4zztHl5JmcTdoe/wCbB57x WHUI39TyrcDwt5DPVPV8BPk= =Kp/i -----END PGP SIGNATURE----- --2tb6s275ZjQu9Nb2--
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