Date: Sat, 06 Oct 2012 08:09:29 +0200 From: Peter Maloney <peter.maloney@brockmann-consult.de> To: ram_chander250@yahoo.com Cc: freebsd-fs@freebsd.org Subject: Re: Zfs import issue Message-ID: <506FCB19.8010703@brockmann-consult.de> In-Reply-To: <CAMRGQbOAFydK8YNeG=9UCMFTcdHmQdJWBoBYaVxVDj2THpDHSw@mail.gmail.com> References: <CAMRGQbN=zwPktyZjfMoymA8PzrJqG=8mgUB2x5W4UVTMT3sdqA@mail.gmail.com> <506C3EFC.2060602@FreeBSD.org> <506D55B5.70403@brockmann-consult.de> <CAMRGQbOAFydK8YNeG=9UCMFTcdHmQdJWBoBYaVxVDj2THpDHSw@mail.gmail.com>
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Okay, then we have the same problem except I need one more zfs command after the send to hang the filesystem. In my case, this means I can simply never call zfs twice before the first is done. eg. a file based lock in my scripts; or wrap the zfs command with something that locks. Does this solve (workaround) your problem? I find (in 8.2-STABLE, 8.3-STABLE) the file system works 100% during a send unless there is something else with a "zfs" command that happens; only zfs commands will hang/block , not ls, df, etc.; in my example below, I destroyed a snapshot, and that command hung/blocked. And when the hung/blocked zfs command is a write command, such as destroy, then the filesystem is hung/blocked too, including ls, df, etc.. And when a hung/blocked command is killed, it seems to be permanently hung (but could just be enormously slow). On 10/06/2012 05:04 AM, Ram Chander wrote: > Yes importing means "zfs recv" , "df" hangs, "cd " to the filesystem > hangs. Basically entire filesystem is inaccessbile. Once "zfs recv" > completes, all is normal. > > On Thu, Oct 4, 2012 at 2:54 PM, Peter Maloney > <peter.maloney@brockmann-consult.de > <mailto:peter.maloney@brockmann-consult.de>> wrote: > > I find this sort of thing to be common, but not exactly as you > describe. > I don't know if I tried df, but "zfs list" hangs (as well as any other > zfs related command, maybe even zdb). And I don't know what you mean > "importing zfs snapshot", so I'm guessing you mean zfs recv. > > eg. > > zfs send somedataset@somesnapshot | ....... > (leave it running in background) > > zfs list > (works fine; I guess it works because send is read-only) > > zfs destroy somedataset@someothersnapshot > (hang; I guess because this is a write operation, so it needs to wait > for the read lock on zfs send to finish the transaction) > > zfs list > (hang) > > I'm not sure if df hangs too. > > At this point, using kill -9 doesn't solve anything, and if you > kill the > zfs send, it's possible that every zfs command and df will hang. > > And I don't know what, but I'm mostly sure there is something I > can run > that will make even "ls" hang after this point. > > > On 10/03/2012 03:34 PM, Andriy Gapon wrote: > > on 03/10/2012 14:43 Ram Chander said the following: > >> Hi, > >> > >> I am importing zfs snapshot to freebsd-9 from anther host running > >> freebsd-9. When the import happens, it locks the filesystem, > "df" hangs > >> and unable to use the filesystem. Once the import completes, > the filesystem > >> is back to normal and read/write works fine. The same doesnt > happen in > >> Solaris/OpenIndiana. > >> > >> # uname -an > >> FreeBSD hostname 9.0-RELEASE FreeBSD 9.0-RELEASE #0: Tue Jan 3 > 07:46:30 > >> UTC 2012 root@farrell.cse.buffalo.edu:/ > >> usr/obj/usr/src/sys/GENERIC amd64 > >> > >> Zfs ver: 28 > >> > >> > >> Any inputs would be helpful. Is there any way to overcome this > freeze ? > > What if you add -n option to df? > > > > > -- > > -------------------------------------------- > Peter Maloney > Brockmann Consult > Max-Planck-Str. 2 > 21502 Geesthacht > Germany > Tel: +49 4152 889 300 > Fax: +49 4152 889 333 > E-mail: peter.maloney@brockmann-consult.de > <mailto:peter.maloney@brockmann-consult.de> > Internet: http://www.brockmann-consult.de > -------------------------------------------- > > _______________________________________________ > freebsd-fs@freebsd.org <mailto:freebsd-fs@freebsd.org> mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to > "freebsd-fs-unsubscribe@freebsd.org > <mailto:freebsd-fs-unsubscribe@freebsd.org>" > >
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