[DRBD-user] DRBD + OCFS2 - Split-Brain detected but unresolved

Jake Smith jsmith at argotec.com
Tue Apr 17 18:22:14 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


----- Original Message -----
> From: "David Coulson" <david at davidcoulson.net>
> To: "Jacek Osiecki" <cjosh at silvercube.pl>
> Cc: drbd-user at lists.linbit.com
> Sent: Tuesday, April 17, 2012 12:08:47 PM
> Subject: Re: [DRBD-user] DRBD + OCFS2 - Split-Brain detected but unresolved
> 
> http://www.drbd.org/users-guide/s-resolve-split-brain.html
> 
> 
> 
> On Apr 17, 2012, at 11:06 AM, Jacek Osiecki wrote:
> 
> > Hello,
> > 
> > I am currently testing dual-master setup with DRBD+OCFS2.
> > Finally I managed to get it working well on kernel 2.6.39.4, DRBD
> > version 8.3.10 (userland version: 8.4.1) and OCFS2 version 1.5.0.
> > 

I could be wrong but I believe it is bad practice to have userland version != kernel version of DRBD


> > I had some troubles with broken replication, and sometimes I see
> > that
> > automatic recovery sometimes works and sometimes does not. What's
> > strange, is that this still are tests, and actually when one
> > server is fully functional, second one has no processess that even
> > touch the synchronized partition.
> > 
> > In dmesg on the active server it looks like this:
> > 
> > [707152.209885] block drbd0: Handshake successful: Agreed network
> > protocol version 96
> > [707152.209895] block drbd0: conn( WFConnection -> WFReportParams )
> > [707152.210068] block drbd0: Starting asender thread (from
> > drbd0_receiver [1096])
> > [707152.210341] block drbd0: data-integrity-alg: <not-used>
> > [707152.210352] block drbd0: max BIO size = 130560
> > [707152.210359] block drbd0: drbd_sync_handshake:
> > [707152.210363] block drbd0: self
> > 8631CEC3370B5C31:A9BC3587FC5AA879:0BF8587A4ABA37B5:0BF7587A4ABA37B5
> > bits:21 flags:0
> > [707152.210368] block drbd0: peer
> > 73E08E8E06754D97:A9BC3587FC5AA879:0BF8587A4ABA37B5:0BF7587A4ABA37B5
> > bits:0 flags:0
> > [707152.210371] block drbd0: uuid_compare()=100 by rule 90
> > [707152.210377] block drbd0: helper command: /sbin/drbdadm
> > initial-split-brain minor-0
> > [707152.212439] block drbd0: helper command: /sbin/drbdadm
> > initial-split-brain minor-0 exit code 0 (0x0)
> > [707152.212442] block drbd0: Split-Brain detected but unresolved,
> > dropping connection!
> > [707152.212445] block drbd0: helper command: /sbin/drbdadm
> > split-brain minor-0
> > [707152.214134] block drbd0: helper command: /sbin/drbdadm
> > split-brain minor-0 exit code 0 (0x0)
> > [707152.214137] block drbd0: conn( WFReportParams -> Disconnecting
> > )
> > [707152.214141] block drbd0: error receiving ReportState, l: 4!
> > [707152.214150] block drbd0: asender terminated
> > [707152.214154] block drbd0: Terminating drbd0_asender
> > [707152.214177] block drbd0: Connection closed
> > [707152.214180] block drbd0: conn( Disconnecting -> StandAlone )
> > [707152.214188] block drbd0: receiver terminated
> > [707152.214190] block drbd0: Terminating drbd0_receiver
> > 
> > Is there any help for this situation? I don't understand why the
> > case isn't solved, since second server doesn't write to drbd0,
> > sometimes even partition wasn't mounted (I can't be 100% sure, but
> > it seems so).
> > 
> > I would be greatful if you could give me some hint how to make this
> > configuration stable, without sacrificing data on one of nodes
> > (now in order to recover I have to set second node to slave). Any
> > ideas what is wrong in my setup?
> > 
> > P.S. Any suggestions how to measure real performance
> > (read/write/copy) of DRBD+OCFS2? UnixBench gives crazy results
> > (read performance about 10% of local filesystem)...

For DRBD here's a start:
http://www.drbd.org/users-guide-legacy/p-performance.html

> > 
> > Best regards,
> > --
> > Jacek Osiecki
> > josiecki at silvercube.pl
> > 
> > Silvercube s.c.
> > ul. Makuszynskiego 4
> > 31-752 Kraków
> > +48 (12) 684 21 00_______________________________________________
> > drbd-user mailing list
> > drbd-user at lists.linbit.com
> > http://lists.linbit.com/mailman/listinfo/drbd-user
> 
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