Date: Thu, 27 Jun 2013 10:34:22 +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: <47B6A89F-6444-485A-88DD-69A9A93D9B3F@alumni.chalmers.se> In-Reply-To: <5A26ABDE-C7F2-41CC-A3D1-69310AB6BC36@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> <5A26ABDE-C7F2-41CC-A3D1-69310AB6BC36@alumni.chalmers.se>
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Notation for archives. I have so far not experienced any problems with both local (per head unit) and external (on disk enclosure) caches while importing and exporting my pool. Disks I use on both nodes are identical - manufacturer, size, model. da1,da2 - local da32,da33 - external Export/import is done WITHOUT removing/adding local disks. root@nfs1:/root # zpool status pool: jbod state: ONLINE scan: scrub repaired 0 in 0h0m with 0 errors on Wed Jun 26 13:14:55 2013 config: NAME STATE READ WRITE CKSUM jbod ONLINE 0 0 0 raidz3-0 ONLINE 0 0 0 da10 ONLINE 0 0 0 da11 ONLINE 0 0 0 da12 ONLINE 0 0 0 da13 ONLINE 0 0 0 da14 ONLINE 0 0 0 da15 ONLINE 0 0 0 da16 ONLINE 0 0 0 da17 ONLINE 0 0 0 da18 ONLINE 0 0 0 da19 ONLINE 0 0 0 logs mirror-1 ONLINE 0 0 0 da32s1 ONLINE 0 0 0 da33s1 ONLINE 0 0 0 cache da32s2 ONLINE 0 0 0 da33s2 ONLINE 0 0 0 da1 ONLINE 0 0 0 da2 ONLINE 0 0 0 On 25 jun 2013, at 21:22, mxb <mxb@alumni.chalmers.se> wrote: > > 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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