Date: Tue, 25 Jun 2013 21:22:43 +0200 From: mxb <mxb@alumni.chalmers.se> To: Jeremy Chadwick <jdc@koitsu.org> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: zpool export/import on failover - The pool metadata is corrupted Message-ID: <5A26ABDE-C7F2-41CC-A3D1-69310AB6BC36@alumni.chalmers.se> In-Reply-To: <09717048-12BE-474B-9B20-F5E72D00152E@alumni.chalmers.se> References: <D7F099CB-855F-43F8-ACB5-094B93201B4B@alumni.chalmers.se> <CAKYr3zyPLpLau8xsv3fCkYrpJVzS0tXkyMn4E2aLz29EMBF9cA@mail.gmail.com> <016B635E-4EDC-4CDF-AC58-82AC39CBFF56@alumni.chalmers.se> <20130606223911.GA45807@icarus.home.lan> <C3FC39B3-D09F-4E73-9476-3BFC8B817278@alumni.chalmers.se> <20130606233417.GA46506@icarus.home.lan> <61E414CF-FCD3-42BB-9533-A40EA934DB99@alumni.chalmers.se> <09717048-12BE-474B-9B20-F5E72D00152E@alumni.chalmers.se>
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I think I'v found the root of this issue. Looks like "wiring down" disks the same way on both nodes (as suggested) fixes this issue. //mxb On 20 jun 2013, at 12:30, mxb <mxb@alumni.chalmers.se> wrote: > > Well, > > I'm back to square one. > > After some uptime and successful import/export from one node to another, I eventually got 'metadata corruption'. > I had no problem with import/export while for ex. rebooting master-node (nfs1), but not THIS time. > Metdata got corrupted while rebooting master-node?? > > Any ideas? > > [root@nfs1 ~]# zpool import > pool: jbod > id: 7663925948774378610 > state: FAULTED > status: The pool metadata is corrupted. > action: The pool cannot be imported due to damaged devices or data. > see: http://illumos.org/msg/ZFS-8000-72 > config: > > jbod FAULTED corrupted data > raidz3-0 ONLINE > da3 ONLINE > da4 ONLINE > da5 ONLINE > da6 ONLINE > da7 ONLINE > da8 ONLINE > da9 ONLINE > da10 ONLINE > da11 ONLINE > da12 ONLINE > cache > da13s2 > da14s2 > logs > mirror-1 ONLINE > da13s1 ONLINE > da14s1 ONLINE > [root@nfs1 ~]# zpool import jbod > cannot import 'jbod': I/O error > Destroy and re-create the pool from > a backup source. > [root@nfs1 ~]# > > On 11 jun 2013, at 10:46, mxb <mxb@alumni.chalmers.se> wrote: > >> >> Thanks everyone whom replied. >> Removing local L2ARC cache disks (da1,da2) indeed showed to be a cure to my problem. >> >> Next is to test with add/remove after import/export as Jeremy suggested. >> >> //mxb >> >> On 7 jun 2013, at 01:34, Jeremy Chadwick <jdc@koitsu.org> wrote: >> >>> On Fri, Jun 07, 2013 at 12:51:14AM +0200, mxb wrote: >>>> >>>> Sure, script is not perfects yet and does not handle many of stuff, but moving highlight from zpool import/export to the script itself not that >>>> clever,as this works most of the time. >>>> >>>> Question is WHY ZFS corrupts metadata then it should not. Sometimes. >>>> I'v seen stale of zpool then manually importing/exporting pool. >>>> >>>> >>>> On 7 jun 2013, at 00:39, Jeremy Chadwick <jdc@koitsu.org> wrote: >>>> >>>>> On Fri, Jun 07, 2013 at 12:12:39AM +0200, mxb wrote: >>>>>> >>>>>> Then MASTER goes down, CARP on the second node goes MASTER (devd.conf, and script for lifting): >>>>>> >>>>>> root@nfs2:/root # cat /etc/devd.conf >>>>>> >>>>>> >>>>>> notify 30 { >>>>>> match "system" "IFNET"; >>>>>> match "subsystem" "carp0"; >>>>>> match "type" "LINK_UP"; >>>>>> action "/etc/zfs_switch.sh active"; >>>>>> }; >>>>>> >>>>>> notify 30 { >>>>>> match "system" "IFNET"; >>>>>> match "subsystem" "carp0"; >>>>>> match "type" "LINK_DOWN"; >>>>>> action "/etc/zfs_switch.sh backup"; >>>>>> }; >>>>>> >>>>>> root@nfs2:/root # cat /etc/zfs_switch.sh >>>>>> #!/bin/sh >>>>>> >>>>>> DATE=`date +%Y%m%d` >>>>>> HOSTNAME=`hostname` >>>>>> >>>>>> ZFS_POOL="jbod" >>>>>> >>>>>> >>>>>> case $1 in >>>>>> active) >>>>>> echo "Switching to ACTIVE and importing ZFS" | mail -s ''$DATE': '$HOSTNAME' switching to ACTIVE' root >>>>>> sleep 10 >>>>>> /sbin/zpool import -f jbod >>>>>> /etc/rc.d/mountd restart >>>>>> /etc/rc.d/nfsd restart >>>>>> ;; >>>>>> backup) >>>>>> echo "Switching to BACKUP and exporting ZFS" | mail -s ''$DATE': '$HOSTNAME' switching to BACKUP' root >>>>>> /sbin/zpool export jbod >>>>>> /etc/rc.d/mountd restart >>>>>> /etc/rc.d/nfsd restart >>>>>> ;; >>>>>> *) >>>>>> exit 0 >>>>>> ;; >>>>>> esac >>>>>> >>>>>> This works, most of the time, but sometimes I'm forced to re-create pool. Those machines suppose to go into prod. >>>>>> Loosing pool(and data inside it) stops me from deploy this setup. >>>>> >>>>> This script looks highly error-prone. Hasty hasty... :-) >>>>> >>>>> This script assumes that the "zpool" commands (import and export) always >>>>> work/succeed; there is no exit code ($?) checking being used. >>>>> >>>>> Since this is run from within devd(8): where does stdout/stderr go to >>>>> when running a program/script under devd(8)? Does it effectively go >>>>> to the bit bucket (/dev/null)? If so, you'd never know if the import or >>>>> export actually succeeded or not (the export sounds more likely to be >>>>> the problem point). >>>>> >>>>> I imagine there would be some situations where the export would fail >>>>> (some files on filesystems under pool "jbod" still in use), yet CARP is >>>>> already blindly assuming everything will be fantastic. Surprise. >>>>> >>>>> I also do not know if devd.conf(5) "action" commands spawn a sub-shell >>>>> (/bin/sh) or not. If they don't, you won't be able to use things like" >>>>> 'action "/etc/zfs_switch.sh active >> /var/log/failover.log";'. You >>>>> would then need to implement the equivalent of logging within your >>>>> zfs_switch.sh script. >>>>> >>>>> You may want to consider the -f flag to zpool import/export >>>>> (particularly export). However there are risks involved -- userland >>>>> applications which have an fd/fh open on a file which is stored on a >>>>> filesystem that has now completely disappeared can sometimes crash >>>>> (segfault) or behave very oddly (100% CPU usage, etc.) depending on how >>>>> they're designed. >>>>> >>>>> Basically what I'm trying to say is that devd(8) being used as a form of >>>>> HA (high availability) and load balancing is not always possible. >>>>> Real/true HA (especially with SANs) is often done very differently (now >>>>> you know why it's often proprietary. :-) ) >>> >>> Add error checking to your script. That's my first and foremost >>> recommendation. It's not hard to do, really. :-) >>> >>> After you do that and still experience the issue (e.g. you see no actual >>> errors/issues during the export/import phases), I recommend removing >>> the "cache" devices which are "independent" on each system from the pool >>> entirely. Quoting you (for readers, since I snipped it from my previous >>> reply): >>> >>>>>> Note, that ZIL(mirrored) resides on external enclosure. Only L2ARC >>>>>> is both local and external - da1,da2, da13s2, da14s2 >>> >>> I interpret this to mean the primary and backup nodes (physical systems) >>> have actual disks which are not part of the "external enclosure". If >>> that's the case -- those disks are always going to vary in their >>> contents and metadata. Those are never going to be 100% identical all >>> the time (is this not obvious?). I'm surprised your stuff has worked at >>> all using that model, honestly. >>> >>> ZFS is going to bitch/cry if it cannot verify the integrity of certain >>> things, all the way down to the L2ARC. That's my understanding of it at >>> least, meaning there must always be "some" kind of metadata that has to >>> be kept/maintained there. >>> >>> Alternately you could try doing this: >>> >>> zpool remove jbod cache daX daY ... >>> zpool export jbod >>> >>> Then on the other system: >>> >>> zpool import jbod >>> zpool add jbod cache daX daY ... >>> >>> Where daX and daY are the disks which are independent to each system >>> (not on the "external enclosure"). >>> >>> Finally, it would also be useful/worthwhile if you would provide >>> "dmesg" from both systems and for you to explain the physical wiring >>> along with what device (e.g. daX) correlates with what exact thing on >>> each system. (We right now have no knowledge of that, and your terse >>> explanations imply we do -- we need to know more) >>> >>> -- >>> | Jeremy Chadwick jdc@koitsu.org | >>> | UNIX Systems Administrator http://jdc.koitsu.org/ | >>> | Making life hard for others since 1977. PGP 4BD6C0CB | >>> >> >
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