[Linux-cluster] GFS2 fatal: invalid metadata block

Kai Meyer kai at fiber.net
Fri Sep 25 18:31:16 UTC 2009


Sorry for the slow response. We ended up (finally) purchasing some RHEL 
licenses to try and get some phone support for this problem, and came up 
with a plan to salvage what we could. I'll try to offer a brief history 
of the problem in hope you can help me understand this issue a little 
better.
I've posted the relevant logfile entries to the events described here : 
http://kai.gnukai.com/gfs2_meltdown.txt
All the nodes send syslog to a remote server named pxe, so the combined 
syslog for all the nodes plus the syslog server is here: 
http://kai.gnukai.com/messages.txt
We started with a 4 node cluster (nodes 1, 2, 4, 5). The GFS2 filesystem 
was created with the latest CentOS 5.3 had to offer when it was 
released. Node 3 was off at the time the errors occurred, and not part 
of the cluster.
First issue I can recover from syslog is from node 5 (192.168.100.105) 
on Sep 8 14:11:27 was a 'fatal: invalid metadata block' error that 
resulted in the file system being withdrawn.
Next was node 4 (192.168.100.104) to hit a 'fatal: filesystem 
consistency error' that also resulted in the file system being 
withdrawn. On the systems themselves, any attempt to access the 
filesystem would result in a I/O error response. At the prospect of 
rebooting 2 of the 4 nodes in my cluster, I brought node 3 
(192.168.100.103) online first. Then I power cycled nodes 4 and 5 one at 
a time and let them come back online. These nodes are running Xen, so I 
start to bring the VMs that were on nodes 4 and 5 online on nodes 3-5 
after all 3 had joined the cluster.
Shortly thereafter, node 3 encounters the 'fatal: invalid metadata 
block', and withdraws the file system. Then node 2 (.102) encounters 
'fatal: invalid metadata block' also, and withdraws the filesystem. So I 
reboot them.
During their reboot, nodes 1 (.101) and 5 hits the same 'fatal: invalid 
metadata block' error. I waited for nodes 2 and 3 to come back online to 
preserve the cluster. At this point, node 4 was the only node that still 
had the filesystem mounted. After I had rebooted the other 4 nodes, none 
of them could mount the files system after joining the cluster, and node 
4 was spinning on the error:
Sep  8 16:54:22 192.168.100.104 kernel: GFS2: 
fsid=xencluster1:xenclusterfs1.0: jid=4: Trying to acquire journal lock...
Sep  8 16:54:22 192.168.100.104 kernel: GFS2: 
fsid=xencluster1:xenclusterfs1.0: jid=4: Busy
It wasn't until this point that we suspected the SAN. We discovered that 
the SAN had marked a drive as "failed" but did not remove it from the 
array and begin to rebuild on the hot spare. When we physically removed 
the failed drive, the hot spare was picked up and put into the array.
The VMs on node 4 were the only ones "running" but they had all crashed 
because their disk was unavailable. I decided to reboot all the nodes to 
try and re-establish the cluster. We were able to get all the VMs turned 
back on, and we thought we were out of the dark, with the exception of 
the high level of filesystem corruption we caused inside 30% of the VM's 
filesystems. We ran them through their ext3 filesystem checks, and got 
them all running again.

Then at the time I send the original email, we were encountering the 
same invalid metadata block errors on the VMs at different points.

With Redhat on the phone, we decided to migrate as much data as we could 
from the original production SAN to a new SAN, and bring the VMs online 
on the new SAN. There were a total of 3 VM disk images that would not 
copy because they would trigger the invalid metadata block error every 
time. After the migration, we tried 3 filesystem checks, all of which 
failed, leaving the fsck_dlm mechanism configured on the filesystem. We 
were able to override the lock with the instructions here:
http://kbase.redhat.com/faq/docs/DOC-17402

We were able to remount the gfs2 filesystem again, but with out any 
improvement. If we tried to copy those same files, it would withdraw the 
filesystem. We were able to mount the disk images and recover some 
files, and we feel like we got lucky that none of those files also 
triggered the filesystem withdraw.

Today, we feel fairly confident that the underlying issue began with the 
disk being marked as failed, but not being removed from the array. We've 
contacted the hardware vendor of the SAN, but the only response they 
offered was, "That shouldn't have happened, and it shouldn't happen again."


I am very interested in your response, but at this point there isn't any 
urgency. The old production SAN is in the lab, and we are running smart 
tests on each of the disks to see if any of the disks are salvageable. 
The new SAN we put into production has all new drives (different make an 
model), and we hope we don't encounter any further issues.

The last issue I want to investigate is phasing out all my CentOS 5.3 
servers, and installing RHEL 5.4 servers one at a time, so I don't have 
to take down the cluster. The intent is to live migrate all the VMs to 
the RHEL 5.4 servers to keep the availability on the VMs as high as 
possible, but that's another topic I'll probably post about later after 
some testing in the lab.

-Kai Meyer

Steven Whitehouse wrote:
> Hi,
>
> On Sat, 2009-09-19 at 05:16 -0600, Kai Meyer wrote:
>   
>> I have a 5 node cluster running kernel 2.6.18-128.1.6.el5xen and 
>> gfs2-utils-0.1.53-1.el5_3.3 . Twice in 10 days, each node in my cluster 
>> has failed with the same message in /var/log/messages. dmesg reports the 
>> same errors, and on some nodes there are no other entries previous to 
>> the invalid metadata block error.
>>
>> I would like to know what issues can trigger such an event. If it is 
>> more helpful for me to provide more information, I will be happy to, I'm 
>> just not sure what other information you would consider relevant.
>>
>> Thank you for your time,
>> -Kai Meyer
>>
>>     
> It means that the kernel was looking for an indirect block, but instead
> found something that was not an indirect block. The only way to fix this
> is with fsck (after unmounting on all nodes) otherwise the issue is
> likely to continue to occur each time you access the particular inode
> with the problem.
>
> There have been a couple of reports of this (or very similar) issues
> recently. The problem in each case is that the original issue probably
> happened some time before it triggered the message which you've seen.
> That means that it is very tricky to figure out exactly what the cause
> is.
>
> I'd be very interested to know whether this filesystem was a newly
> created gfs2 filesystem or an upgraded gfs1 filesystem. Also, whether
> there have been any other issues, however minor, which might have caused
> a node to be rebooted or fenced since the filesystem was created? Also,
> any other background information about the type of workload that was
> being run on the filesystem would be helpful too.
>
> Steve.
>
>
>   
>> Sep 19 02:02:06 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1: fatal: invalid metadata block
>> Sep 19 02:02:06 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1:   bh = 567447963 (magic number)
>> Sep 19 02:02:06 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1:   function = 
>> gfs2_meta_indirect_buffer, file = fs/gfs2/meta_io.c, line
>> = 334
>> Sep 19 02:02:06 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1: about to withdraw this file system
>> Sep 19 02:02:06 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1: telling LM to withdraw
>> Sep 19 02:02:07 192.168.100.104 kernel: GFS2: 
>> fsid=xencluster1:xenclusterfs1.1: withdrawn
>> Sep 19 02:02:07 192.168.100.104 kernel: 
>> Sep 19 02:02:07 192.168.100.104 kernel: Call Trace:
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff885154ce>] 
>> :gfs2:gfs2_lm_withdraw+0xc1/0xd0
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80262907>] 
>> __wait_on_bit+0x60/0x6e
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80215788>] 
>> sync_buffer+0x0/0x3f
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80262981>] 
>> out_of_line_wait_on_bit+0x6c/0x78
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8029a01a>] 
>> wake_bit_function+0x0/0x23
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8021a7f1>] 
>> submit_bh+0x10a/0x111
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff885284a7>] 
>> :gfs2:gfs2_meta_check_ii+0x2c/0x38
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff88518d30>] 
>> :gfs2:gfs2_meta_indirect_buffer+0x104/0x160
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff88509fc3>] 
>> :gfs2:gfs2_block_map+0x1dc/0x33e
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8021a821>] 
>> poll_freewait+0x29/0x6a
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8850a199>] 
>> :gfs2:gfs2_extent_map+0x74/0xac
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8850a2ce>] 
>> :gfs2:gfs2_write_alloc_required+0xfd/0x122
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff885128d5>] 
>> :gfs2:gfs2_glock_nq+0x248/0x273
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8851a27c>] 
>> :gfs2:gfs2_write_begin+0x99/0x36a
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8851bd1b>] 
>> :gfs2:gfs2_file_buffered_write+0x14b/0x2e5
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8020d3a5>] 
>> file_read_actor+0x0/0xfc
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8851c151>] 
>> :gfs2:__gfs2_file_aio_write_nolock+0x29c/0x2d4
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8851c2f4>] 
>> :gfs2:gfs2_file_write_nolock+0xaa/0x10f
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8022eca0>] 
>> __wake_up+0x38/0x4f
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80299fec>] 
>> autoremove_wake_function+0x0/0x2e
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8022fbe4>] 
>> pipe_readv+0x38e/0x3a2
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80263bce>] 
>> lock_kernel+0x1b/0x32
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8851c444>] 
>> :gfs2:gfs2_file_write+0x49/0xa7
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff80216da9>] 
>> vfs_write+0xce/0x174
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff802175e1>] 
>> sys_write+0x45/0x6e
>> Sep 19 02:02:07 192.168.100.104 kernel:  [<ffffffff8025f2f9>] 
>> tracesys+0xab/0xb6
>>
>> --
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>>     
>
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