Date: Fri, 24 Mar 2006 12:58:09 +0100 (CET) From: "Julien Gabel" <jpeg@thilelli.net> To: "Kris Kennaway" <kris@obsecurity.org> Cc: Eugene <genie@geniechka.ru>, freebsd-fs@freebsd.org Subject: Re: UFS2 Snapshots in 6.1-Beta4 - Confirmed Problems. Message-ID: <59591.145.248.192.4.1143201489.squirrel@webmail.thilelli.net> In-Reply-To: <20060323213941.GA88109@xor.obsecurity.org> References: <20060322120033.E5B8916A44B@hub.freebsd.org> <007801c64eb9$3db4c050$1b12c055@genie> <50319.192.168.1.101.1143148607.squirrel@webmail.thilelli.net> <20060323213941.GA88109@xor.obsecurity.org>
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>>> While we're on the topic of snapshots, I recently posted this >>> follow-up to the PR kern/66270 "[hang] dump causes machine freeze" >>>> I wonder what is the status of this PR? >>>> I seem to have the same problem with 5.3-RELEASE. >>>> >>>> Before this started, system worked nicely for more than a year and >>>> then it started to hang during dump (seemingly just after mksnap_ffs) >>>> first intermittently and now reproducibly (might increase in data >>>> size be a factor? though disk is only about 18% full). >>>> Originally it hanged and console had complains about increasing >>>> PMAP_SHPGPERPROC and maxproc. >>>> After some talk in freebsd-fs, I adjusted these parameters and now >>>> it just hangs without complaining =(( >>>> >>>> Any suggestions? >>> In addition to this PR, I found a couple of similar threads in >>> different lists but they all just have some initial talk and >>> preliminary analysis, and then it just stops. Was that snapshot >>> problem fixed or is it the same as we are talking now? I can't >>> believe I am the only one in almost 2 years who is (trying to be) >>> doing automated backups... >>> So, if it was fixed, when (which version)? If not, then when it might >>> be and -- in the meantime -- is there any workaround for backups? >>> (The system is the production server on the colocation so doing >>> backups in single-user mode is not practical). >> Interesting. I used dump/restore without problem on i386 using a file >> system of 120Go. I swiched two weeks ago on amd64 using a file system >> of 260Go and encountered the very same behavior (hang, freeze). Don't >> know if it is related to the new processor architecture or the bigger >> fs size, but i didn't observe this hang on smallest file system before. >> >> Because i am a big fan of dump, i currently choose to use it without the >> '-L' switch, back to the old (classical?) behavior, i.e. not doing a >> snapshot before doing the dump. It is always better than not having >> complete system backup at all (YMMV, though). >> >> I am currently running 6.1-PRERELEASE build Wed Mar 22 03:55:42 CET >> 2006. > Let us know if it recurs with your updated kernel. Well, it seems ok now with FreeBSD 6.1-PRERELEASE #0 Fri Mar 24 03:58 CET 2006. During the creation of the snapshot (either with mksnap_ffs(8) or with `dump -L'), the system was not particularly "responsiveness", but it seems to be the expected behavior. FYI, for an UFSv2 file system of 260Go with currently ~6.5Go used, it took approximatively ~15mn (on recent hardware). Globally, and minus the ~15mn of not very good serviceability (http requests time-out -- or very, very slow to be served -- and interactive shells not very responsive), all seems ok : the snapshot doesn't hang or freeze the system globally anymore, and the backup are made correctly using `dump -L'). So, good news. -- -jpeg.
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