Do you have any more details, like - 1) when the system was "hung", was the client still flushing data to the nfs server? Any network activity? The backtrace below shows that the system was just waiting for a long time waiting for a write to complete.
2) anything in the gluster nfs logs? 3) is it possible DHCP assigned a different IP while renewing lease? Avati On Fri, Mar 22, 2013 at 3:04 AM, Ian Latter <ian.lat...@midnightcode.org>wrote: > Hello, > > > This is a problem that I've been chipping at on and off for a while and > its finally cost me one recording too many - I just want to get it cured - > any > help would be greatly appreciated. > > I'm using the kernel NFS client on a number of Linux machines (four, I > believe), to map back to two Gluster 3.3.0 shares. > > I have seen Linux Mint and Ubuntu machines of various generations and > configurations (one is 64bit) hang intermittently on either one of the two > Gluster shares on "access" (I can't say if its writing or not - the below > log > is for a write). But by far the most common failure example is my MythTV > Backend server. It has 5 tuners pulling down up to a gigabyte per hour > each directly to an NFS share from Gluster 3.3.30 with two local 3TB > drives in a "distribute" volume. It also re-parses each recording for Ad > filtering, so the share gets a good thrashing. The myth backend box would > fail (hang the system) once each 2-4 days. > > The backend server was also updating its NIC via DHCP. I have been using > an MTU of 1460 and each DHCP event would thus result in this note in syslog; > [ 12.248640] r8169: WARNING! Changing of MTU on this NIC may lead to > frame reception errors! > > I change the DHCP MTU to 1500 and didn't see an improvement. So, the > last change I made was a hard coded address and default MTU (of 1500). > The most recent trial saw a 13 day run time which is well outside the norm, > but it still borked (one test only - may have been lucky). > > >> syslog burp; > [1204800.908075] INFO: task mythbackend:21353 blocked for more than 120 > seconds. > [1204800.908084] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [1204800.908091] mythbackend D f6af9d28 0 21353 1 0x00000000 > [1204800.908107] f6af9d38 00000086 00000002 f6af9d28 f6a4e580 c05d89e0 > c08c3700 c08c3700 > [1204800.908123] bd3a4320 0004479c c08c3700 c08c3700 bd3a0e4e 0004479c > 00000000 c08c3700 > [1204800.908138] c08c3700 f6a4e580 00000001 f6a4e580 c2488700 f6af9d80 > f6af9d48 c05c6e51 > [1204800.908152] Call Trace: > [1204800.908170] [<c05c6e51>] io_schedule+0x61/0xa0 > [1204800.908180] [<c01d9c4d>] sync_page+0x3d/0x50 > [1204800.908190] [<c05c761d>] __wait_on_bit+0x4d/0x70 > [1204800.908197] [<c01d9c10>] ? sync_page+0x0/0x50 > [1204800.908211] [<c01d9e71>] wait_on_page_bit+0x91/0xa0 > [1204800.908221] [<c0165e60>] ? wake_bit_function+0x0/0x50 > [1204800.908229] [<c01da1f4>] filemap_fdatawait_range+0xd4/0x150 > [1204800.908239] [<c01da3c7>] filemap_write_and_wait_range+0x77/0x80 > [1204800.908248] [<c023aad4>] vfs_fsync_range+0x54/0x80 > [1204800.908257] [<c023ab5e>] generic_write_sync+0x5e/0x80 > [1204800.908265] [<c01dbda1>] generic_file_aio_write+0xa1/0xc0 > [1204800.908292] [<fb0bc94f>] nfs_file_write+0x9f/0x200 [nfs] > [1204800.908303] [<c0218454>] do_sync_write+0xa4/0xe0 > [1204800.908314] [<c032e626>] ? apparmor_file_permission+0x16/0x20 > [1204800.908324] [<c0302a74>] ? security_file_permission+0x14/0x20 > [1204800.908333] [<c02185d2>] ? rw_verify_area+0x62/0xd0 > [1204800.908342] [<c02186e2>] vfs_write+0xa2/0x190 > [1204800.908350] [<c02183b0>] ? do_sync_write+0x0/0xe0 > [1204800.908359] [<c0218fa2>] sys_write+0x42/0x70 > [1204800.908367] [<c05c90a4>] syscall_call+0x7/0xb > > This might suggest a hardware fault on the Myth Backend host (like the > NIC) but I don't believe that to be the case because I've seen the same > issue on other clients. I suspect that they are much more rare because > the data volume on those clients pales in comparison to the Myth Backend > process (virtual guests, etc - light work - months between failures, > doesn't > feel time related). > > The only cure is a hard reset (of the host with the NFS client) as any FS > operation on that share hangs - including df, ls, sync and umount - so the > system fails to shutdown. > > The kernel on the Myth Backend host isn't new .. > > >> uname -a; > Linux jupiter 2.6.35-22-generic #33-Ubuntu SMP Sun Sep 19 20:34:50 UTC > 2010 i686 GNU/Linux > > Is there a known good/bad version for the kernel/NFS client? Am I under > that bar? > > > The GlusterFS NFS server an embedded platform (Saturn) that has been > running for 74 days; > > >> uptime output; > 08:39:07 up 74 days, 22:16, load average: 0.87, 0.94, 0.94 > > It is a much more modern platform; > > >> uname -a; > Linux (none) 3.2.14 #1 SMP Tue Apr 10 12:46:47 EST 2012 i686 GNU/Linux > > It has had one error in all of that time; > >> dmesg output; > Pid: 4845, comm: glusterfsd Not tainted 3.2.14 #1 > Call Trace: > [<c10512d0>] __rcu_pending+0x64/0x294 > [<c1051640>] rcu_check_callbacks+0x87/0x98 > [<c1034521>] update_process_times+0x2d/0x58 > [<c1047bdf>] tick_periodic+0x63/0x65 > [<c1047c2d>] tick_handle_periodic+0x17/0x5e > [<c1015ae9>] smp_apic_timer_interrupt+0x67/0x7a > [<c1b2a691>] apic_timer_interrupt+0x31/0x40 > > .. this occurred months ago. > > Unfortunately due to its embedded nature, there are no logs coming from > this platform, only a looped buffer for syslog (and gluster doesn't seem to > syslog). In previous discussions here (months ago) you'll see where I was > working to disable/remove logging from GlusterFS so that I could keep it > alive in an embedded environment - this is the current run configuration. > > The Myth Backend host only mounts one of the two NFS shares, but I've seen > the fault on the hosts that only mount the other - so I'm reluctant to > believe that its a hardware failure at the Drive level on the Saturn / > Gluster > server. > > The /etc/fstab entry for this share, on the Myth Backend host, is; > > saturn:/recordings /var/lib/mythtv/saturn_recordings nfs > nfsvers=3,rw,rsize=8192,wsize=8192,hard,intr,sync,dirsync,noac,noatime,nodev,nosuid > 0 0 > > When I softened this to async with soft failures (a config taken straight > from the Gluster site/FAQ) it crashed out in a much shorter time-frame > (less than a day, one test only - may have been unlucky); > > saturn:/recordings /var/lib/mythtv/saturn_recordings nfs > defaults,_netdev,nfsvers=3,proto=tcp 0 0 > > > Other than the high use Myth Backend host I've failed to accurately nail > down the trigger for this issue - which is making diagnostics painful (I > like > my TV too much to do more than reboot the failed box - and heaven forbid > the dad that fails to record Pepper Pig!). > > > Any thoughts? Beyond enabling logs on the Saturn side ... > > Is it possible this is a bug that was reaped in later versions of Gluster? > > Appreciate being set straight .. > > > > > > Cheers, > > > > > -- > Ian Latter > Late night coder .. > http://midnightcode.org/ > > _______________________________________________ > Gluster-devel mailing list > Gluster-devel@nongnu.org > https://lists.nongnu.org/mailman/listinfo/gluster-devel >
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