[Pacemaker] drbd under pacemaker - always get split brain

Wed Jul 11 07:23:13 UTC 2012

> > It really really looks like Pacemaker is too fast when promoting to
> > primary ... before the connection to the already up second node can be
> > established.
> 
> Do you mean we're violating a constraint?
> Or is it a problem of the RA returning too soon?
dunno, I tried older drbd userspaces to check if it's not problem
of newer RA, to no avail...

> 
> > I see in your logs you have DRBD 8.3.13 userland  but
> > 8.3.11 DRBD module installed ... can you test with 8.3.13 kernel module
> > ... there have been fixes that look like addressing this problem.
tried 8.3.13 userspace + 8.3.13 module (on top of 3.0.36 kernel), unfortunately same result..

> >
> > Another quick-fix, that should also do: add a start-delay of some
> > seconds to the start operation of DRBD
> >
> > ... or fix your after-split-brain policies to automatically solve this
> > special type of split-brain (with 0 blocks to sync).
I'll try that, although I'd not like to use this for production :)

> >
> > Best Regards,
> > Andreas
> >
> > --
> > Need help with Pacemaker?
> > http://www.hastexo.com/now
> >
> >>
> >> thanks for Your time.
> >> n.
> >>
> >>
> >>>
> >>> Regards,
> >>> Andreas
> >>>
> >>> --
> >>> Need help with Pacemaker?
> >>> http://www.hastexo.com/now
> >>>
> >>> >
> >>> > thanks a lot in advance
> >>> >
> >>> > nik
> >>> >
> >>> >
> >>> > On Sun, Jul 08, 2012 at 12:47:16AM +0200, Andreas Kurz wrote:
> >>> >> On 07/02/2012 11:49 PM, Nikola Ciprich wrote:
> >>> >>> hello,
> >>> >>>
> >>> >>> I'm trying to solve quite mysterious problem here..
> >>> >>> I've got new cluster with bunch of SAS disks for testing purposes.
> >>> >>> I've configured DRBDs (in primary/primary configuration)
> >>> >>>
> >>> >>> when I start drbd using drbdadm, it get's up nicely (both nodes
> >>> >>> are Primary, connected).
> >>> >>> however when I start it using corosync, I always get split-brain, although
> >>> >>> there are no data written, no network disconnection, anything..
> >>> >>
> >>> >> your full drbd and Pacemaker configuration please ... some snippets from
> >>> >> something are very seldom helpful ...
> >>> >>
> >>> >> Regards,
> >>> >> Andreas
> >>> >>
> >>> >> --
> >>> >> Need help with Pacemaker?
> >>> >> http://www.hastexo.com/now
> >>> >>
> >>> >>>
> >>> >>> here's drbd resource config:
> >>> >>> primitive drbd-sas0 ocf:linbit:drbd \
> >>> >>>     params drbd_resource="drbd-sas0" \
> >>> >>>     operations $id="drbd-sas0-operations" \
> >>> >>>     op start interval="0" timeout="240s" \
> >>> >>>     op stop interval="0" timeout="200s" \
> >>> >>>     op promote interval="0" timeout="200s" \
> >>> >>>     op demote interval="0" timeout="200s" \
> >>> >>>     op monitor interval="179s" role="Master" timeout="150s" \
> >>> >>>     op monitor interval="180s" role="Slave" timeout="150s"
> >>> >>>
> >>> >>> ms ms-drbd-sas0 drbd-sas0 \
> >>> >>>    meta clone-max="2" clone-node-max="1" master-max="2" master-node-max="1" notify="true" globally-unique="false" interleave="true" target-role="Started"
> >>> >>>
> >>> >>>
> >>> >>> here's the dmesg output when pacemaker tries to promote drbd, causing the splitbrain:
> >>> >>> [  157.646292] block drbd2: Starting worker thread (from drbdsetup [6892])
> >>> >>> [  157.646539] block drbd2: disk( Diskless -> Attaching )
> >>> >>> [  157.650364] block drbd2: Found 1 transactions (1 active extents) in activity log.
> >>> >>> [  157.650560] block drbd2: Method to ensure write ordering: drain
> >>> >>> [  157.650688] block drbd2: drbd_bm_resize called with capacity == 584667688
> >>> >>> [  157.653442] block drbd2: resync bitmap: bits=73083461 words=1141930 pages=2231
> >>> >>> [  157.653760] block drbd2: size = 279 GB (292333844 KB)
> >>> >>> [  157.671626] block drbd2: bitmap READ of 2231 pages took 18 jiffies
> >>> >>> [  157.673722] block drbd2: recounting of set bits took additional 2 jiffies
> >>> >>> [  157.673846] block drbd2: 0 KB (0 bits) marked out-of-sync by on disk bit-map.
> >>> >>> [  157.673972] block drbd2: disk( Attaching -> UpToDate )
> >>> >>> [  157.674100] block drbd2: attached to UUIDs 0150944D23F16BAE:0000000000000000:8C175205284E3262:8C165205284E3263
> >>> >>> [  157.685539] block drbd2: conn( StandAlone -> Unconnected )
> >>> >>> [  157.685704] block drbd2: Starting receiver thread (from drbd2_worker [6893])
> >>> >>> [  157.685928] block drbd2: receiver (re)started
> >>> >>> [  157.686071] block drbd2: conn( Unconnected -> WFConnection )
> >>> >>> [  158.960577] block drbd2: role( Secondary -> Primary )
> >>> >>> [  158.960815] block drbd2: new current UUID 015E111F18D08945:0150944D23F16BAE:8C175205284E3262:8C165205284E3263
> >>> >>> [  162.686990] block drbd2: Handshake successful: Agreed network protocol version 96
> >>> >>> [  162.687183] block drbd2: conn( WFConnection -> WFReportParams )
> >>> >>> [  162.687404] block drbd2: Starting asender thread (from drbd2_receiver [6927])
> >>> >>> [  162.687741] block drbd2: data-integrity-alg: <not-used>
> >>> >>> [  162.687930] block drbd2: drbd_sync_handshake:
> >>> >>> [  162.688057] block drbd2: self 015E111F18D08945:0150944D23F16BAE:8C175205284E3262:8C165205284E3263 bits:0 flags:0
> >>> >>> [  162.688244] block drbd2: peer 7EC38CBFC3D28FFF:0150944D23F16BAF:8C175205284E3263:8C165205284E3263 bits:0 flags:0
> >>> >>> [  162.688428] block drbd2: uuid_compare()=100 by rule 90
> >>> >>> [  162.688544] block drbd2: helper command: /sbin/drbdadm initial-split-brain minor-2
> >>> >>> [  162.691332] block drbd2: helper command: /sbin/drbdadm initial-split-brain minor-2 exit code 0 (0x0)
> >>> >>>
> >>> >>> to me it seems to be that it's promoting it too early, and I also wonder why there is the
> >>> >>> "new current UUID" stuff?
> >>> >>>
> >>> >>> I'm using centos6, kernel 3.0.36, drbd-8.3.13, pacemaker-1.1.6
> >>> >>>
> >>> >>> could anybody please try to advice me? I'm sure I'm doing something stupid, but can't figure out what...
> >>> >>>
> >>> >>> thanks a lot in advance
> >>> >>>
> >>> >>> with best regards
> >>> >>>
> >>> >>> nik
> >>> >>>
> >>> >>>
> >>> >>>
> >>> >>> _______________________________________________
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> >>> >>>
> >>> >>
> >>> >>
> >>> >>
> >>> >>
> >>> >>
> >>> >
> >>> >
> >>> >
> >>> >> _______________________________________________
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> >>> >>
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> >>> >
> >>> >
> >>> >
> >>> >
> >>> > _______________________________________________
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> >>> >
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> >>> >
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
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> >>
> >>
> >> --
> >> -------------------------------------
> >> Ing. Nikola CIPRICH
> >> LinuxBox.cz, s.r.o.
> >> 28.rijna 168, 709 00 Ostrava
> >>
> >> tel.:   +420 591 166 214
> >> fax:    +420 596 621 273
> >> mobil:  +420 777 093 799
> >> www.linuxbox.cz
> >>
> >> mobil servis: +420 737 238 656
> >> email servis: servis at linuxbox.cz
> >> -------------------------------------
> >>
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> >>
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> >>
> >
> >
> >
> >
> > _______________________________________________
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> >
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> >
> 
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-- 
-------------------------------------
Ing. Nikola CIPRICH
LinuxBox.cz, s.r.o.
28.rijna 168, 709 00 Ostrava

tel.:   +420 591 166 214
fax:    +420 596 621 273
mobil:  +420 777 093 799
www.linuxbox.cz

mobil servis: +420 737 238 656
email servis: servis at linuxbox.cz
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