Date: Wed, 15 Oct 2008 20:48:09 +1100 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Jeremy Chadwick <koitsu@FreeBSD.org> Cc: freebsd-stable@FreeBSD.org Subject: Re: System hanging during dump Message-ID: <20081015094809.GG26536@server.vk2pj.dyndns.org> In-Reply-To: <20081015090848.GA72852@icarus.home.lan> References: <20081015082428.GE26536@server.vk2pj.dyndns.org> <20081015083538.GA72190@icarus.home.lan> <20081015085843.GF26536@server.vk2pj.dyndns.org> <20081015090848.GA72852@icarus.home.lan>
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--Ls2Gy6y7jbHLe9Od Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2008-Oct-15 02:08:48 -0700, Jeremy Chadwick <koitsu@FreeBSD.org> wrote: >On Wed, Oct 15, 2008 at 07:58:43PM +1100, Peter Jeremy wrote: >> On 2008-Oct-15 01:35:38 -0700, Jeremy Chadwick <koitsu@FreeBSD.org> wrot= e: >> >On Wed, Oct 15, 2008 at 07:24:28PM +1100, Peter Jeremy wrote: >> >> Last night, I attempted a full, compressed backup of my 181GB /home >> >> (on a PATA disk) to a remote system. The backup started at 2159 and >> >> everything appeared normal until about 0040 when the system became >> >> non-responsive and this lasted until the dump completed at 1033. This >> >> is the first full backup of /home I've made for several years (due to >> >> lack of space). >> ... >> >It's a known problem documented in my Wiki -- see "dump/restore". Note >> >the part about UFS2 snapshot generation. I'm almost certain this is >> >what you're describing. >>=20 >> * UFS2 snapshot generation (mksnap_ffs, dump -L) takes too long; system = is unusable during this time >> In my case, snapshot creation took ~4 minutes. The system was >> running normally for 2.6 hours after snapshot creation completed >> before it froze. > >Did you read the References, including the one from myself? Yes. In my case, dump started and ran mksnap_ffs. About 4 minutes later, actual dumping started and data streaming continued for about 12.6 hours. The system froze about 2.6 hours into the dump (after dump had written about 31GB). >Snapshot generation in some cases took only minutes, but *removal* of >the generated the snapshot took 1.5 hours or more, hanging the system >until the removal was complete. Based on progress reports from both dump and my fifo process, the snapshot removal began about 10 hours _after_ the system froze (during this time, dump wrote about 143GB). Given the timeline, it's fairly clear that neither mksnap_ffs nor the 'rm snapshot' were running at the time the system froze. I am therefore quite confident that the problem I saw is not related to either creation or removal of snapshots. I have been using FreeBSD snapshots for many years and am quite familiar with their quirks. I have never seen this particular problem before. (And FWIW, I _am_ using Doug Ambrisko's patch to ffs_snapshot.c). --=20 Peter Jeremy Please excuse any delays as the result of my ISP's inability to implement an MTA that is either RFC2821-compliant or matches their claimed behaviour. --Ls2Gy6y7jbHLe9Od Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkj1vFkACgkQ/opHv/APuIfmUgCdEe0Dhb8rl/ex8rl4qe2p7ZvO WaUAoIvgREtW4FIiV62mWHtiC90vZDx6 =FpOu -----END PGP SIGNATURE----- --Ls2Gy6y7jbHLe9Od--
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