[Ocfs2-users] any way to ignore quorum in a two node cluster
with one node down?
Andrew D. Ball
aball at linux.vnet.ibm.com
Sun Jul 22 11:22:23 PDT 2007
I'm using a flat file database that I wrote. We use ocfs2 for other
things as well, so it's not as silly as it sounds... 8-)
The renaming happens while modifying a record, which really ought not to
fail if we can help it. I have a simple algorithm to make this
operation transactional, but really want to avoid unnecessary failures.
In my understanding, the failures we've seen occur when a healthy node
is updating the database. Of course I'll work through alternatives.
Peace,
Andrew
On Sat, 2007-07-21 at 15:44 -0700, Sunil Mushran wrote:
> No. Adding a node will not help.It's a node death during the said
> operation that is causing the temporary failure.
>
> I am curious as to why is this such "big" issue for you. Can you elaborate
> on that?
>
> As this has been addressed in mainline, it will work as expected in 1.4.
>
> Andrew D. Ball wrote:
> > Given that the change is non-trivial, would requiring at least three
> > nodes to be in the ocfs2 be a successful workaround?
> >
> > Thanks for your help,
> > Andrew
> >
> > On Fri, 2007-07-20 at 10:10 -0700, Sunil Mushran wrote:
> >
> >> There are dlm bug fixes that should already be in SLES10 SP1.
> >>
> >> The change for what you are looking for was not trivial and
> >> merging it in the 1.2 tree will not be either.
> >>
> >> Some of the patches related to this are as follows:
> >>
> >> Date: Fri Sep 8 11:37:32 2006 -0700
> >>
> >> commit 3384f3df5ed939a25135e1b2734fb7cdee1720a8
> >> ocfs2: Allow binary names in the DLM
> >>
> >> commit ea5b3a187e2724fa9d08b2fbd3898c149ed95c6b
> >> ocfs2: Update dlmfs for new dlmlock() API
> >>
> >> commit f0681062b8e369d9fb6f3ce10f4e3fc8cea5f910
> >> ocfs2: Update dlmglue for new dlmlock() API
> >>
> >> commit d680efe9d8fe0eb99d9dd063a4def6b362cdb40d
> >> ocfs2: Add new cluster lock type
> >>
> >> commit 80c05846f604bab6d61e9732c262420ee9f5f358
> >> ocfs2: Add dentry tracking API
> >>
> >> commit 379dfe9d0db99ed33fb089fcb9c07f5f92566e9e
> >> ocfs2: Hook rest of the file system into dentry locking API
> >>
> >> commit 1390334b4c697b7588d5661fcf6acaeec409cf4c
> >> ocfs2: Remove the dentry vote
> >>
> >> commit 1ba9da2ffa54b56a6346746248bfa38124d499a6
> >> ocfs2: manually d_move() during ocfs2_rename()
> >>
> >> Needless to add, this changes the dlm protocol.
> >>
> >> Andrew D. Ball wrote:
> >>
> >>> Can you help me determine which patches need to be backported to SLES 10
> >>> SP1 to resolve this? Someone in the LTC saw the following that looked
> >>> promising:
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=2f5bf1f2d061dea5146aa283685ce2b00cea2f3d
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=78062cb2e54ffe0df811dce5e68b54da9b8c9025
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b36c3f84988eebf38acaccc756e05f6b70e333ab
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3fca0894a4b5e52c278421b04435b88e32b423ad
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0dd82141b236ce36253e3056c6068ee3d5732196
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e4968476a9bc5a6b30076076b4f3ce3e692e0d79
> >>>
> >>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f3f854648de64c4b6f13f6f13113bc9525c621e5
> >>>
> >>>
> >>> Thanks!
> >>> Andrew
> >>>
> >>> On Tue, 2007-07-17 at 16:17 -0700, Sunil Mushran wrote:
> >>>
> >>>
> >>>> Ahh... this is a 1.2 "feature". :)
> >>>>
> >>>> In 1.2, the fs does messaging (votes) for mount/umount, rename,
> >>>> unlink and delete. So the said operations can fail... if a node dies
> >>>> during the voting process.
> >>>>
> >>>> We have addressed this issue in mainline. Sometime in 2.6.18/19.
> >>>> As in, rename, unlink and delete now use the dlm and thus should
> >>>> no longer fail on a node death.
> >>>>
> >>>> Andrew D. Ball wrote:
> >>>>
> >>>>
> >>>>> >From /var/log/messages:
> >>>>>
> >>>>> Jul 16 17:06:43 enva11 kernel: (29933,2):ocfs2_broadcast_vote:725 ERROR:
> >>>>> status
> >>>>> = -107
> >>>>> Jul 16 17:06:43 enva11 kernel: (29933,2):ocfs2_do_request_vote:798
> >>>>> ERROR: status
> >>>>> = -107
> >>>>> Jul 16 17:06:43 enva11 kernel: (29933,2):ocfs2_rename:1196 ERROR: status
> >>>>> = -107
> >>>>>
> >>>>> The userspace error is a failed invocation of the mv command. I know
> >>>>> that the return code is not 0, but didn't capture it. I can re-run
> >>>>> tomorrow if that would be helpful.
> >>>>>
> >>>>> Thanks for your prompt response!
> >>>>>
> >>>>> Peace,
> >>>>> Andrew
> >>>>>
> >>>>> On Tue, 2007-07-17 at 15:31 -0700, Sunil Mushran wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>> It should behavw as you expect it to. That's the idea.
> >>>>>> What are the errors when mkdir fails?
> >>>>>> As in, userspace and dmesg.
> >>>>>>
> >>>>>> Andrew D. Ball wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> I would really like to see the following behavior:
> >>>>>>>
> >>>>>>> (1) I start with a two-node cluster, both nodes online, with an ocfs2
> >>>>>>> filesystem mounted on both nodes.
> >>>>>>> (2) I power off one of the nodes without unmounting the filesystem.
> >>>>>>> (3) The node that is still powered on continues to use the filesystem
> >>>>>>> mounted read-write with no problems.
> >>>>>>>
> >>>>>>> I believe I'm seeing that the node that is still online fails to write
> >>>>>>> data to the filesystem. Specifically, mkdir(2) is failing.
> >>>>>>>
> >>>>>>> This is related to having a quorum right? Can the quorum requirements
> >>>>>>> be disabled? I have a file-backed database on the filesystem and my
> >>>>>>> entire software stack will be broken if any surviving nodes cannot
> >>>>>>> update the database. Is there any reason why ignoring the quorum would
> >>>>>>> be not a good idea?
> >>>>>>>
> >>>>>>> Thanks for your help,
> >>>>>>> Andrew
> >>>>>>>
> >>>>>>>
> >>>>>>> _______________________________________________
> >>>>>>> Ocfs2-users mailing list
> >>>>>>> Ocfs2-users at oss.oracle.com
> >>>>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-users
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>> _______________________________________________
> >>>>> Ocfs2-users mailing list
> >>>>> Ocfs2-users at oss.oracle.com
> >>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-users
> >>>>>
> >>>>>
> >>>>>
> >>>
> >>>
> >
> >
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