[DRBD-user] Just restarting secondary causes split brain, cansomeone expain why please?

Francesco Ciocchetti francesco.ciocchetti at kyneste.com
Tue Mar 6 14:39:08 CET 2007

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


is DRBD correctly starting on hydrogen? do you have session established
beetween nodes (it does not seem so).
what about the logs? there is something there that can justify a
situation like this?
what if you try to force connection and primary state or to invalidate peer?

bye
Francesco

David wrote:
> Francesco Ciocchetti wrote:
>> I' ve a newbie about DRBD but i experienced a problem like your one. In
>> my case the problem was the setting of the following configuration
>> instructions:
>>
>> I had to change the first one to this value to be able to regain from
>> the SB.
>>
>>
>> after-sb-0pri discard-younger-primary;
>> after-sb-1pri consensus;
>> after-sb-2pri disconnect;
>>
>>
>> Bye
>>
>> David wrote:
>>  
>>> Before reboot:
>>>
>>> hydrogen:/etc/ha.d # cat /proc/drbd
>>> version: 8.0.1 (api:86/proto:86)
>>> SVN Revision: 2784 build by root at hydrogen, 2007-03-05 08:47:01
>>> 0: cs:Connected st:Primary/Secondary ds:UpToDate/UpToDate C r---
>>> ns:264 nr:0 dw:256 dr:580 al:0 bm:2 lo:0 pe:0 ua:0 ap:0
>>> resync: used:0/31 hits:20 misses:2 starving:0 dirty:0 changed:2
>>> act_log: used:0/127 hits:25 misses:0 starving:0 dirty:0 changed:0
>>>
>>> oxygen:~ # cat /proc/drbd
>>> version: 8.0.1 (api:86/proto:86)
>>> SVN Revision: 2784 build by root at oxygen, 2007-03-05 08:43:02
>>> 0: cs:Connected st:Secondary/Primary ds:UpToDate/UpToDate C r---
>>> ns:0 nr:264 dw:264 dr:0 al:0 bm:2 lo:0 pe:0 ua:0 ap:0
>>> resync: used:0/31 hits:20 misses:2 starving:0 dirty:0 changed:2
>>> act_log: used:0/127 hits:0 misses:0 starving:0 dirty:0 changed:0
>>>
>>>
>>> During hydrogen reboot:
>>> oxygen:~ # cat /proc/drbd
>>> version: 8.0.1 (api:86/proto:86)
>>> SVN Revision: 2784 build by root at oxygen, 2007-03-05 08:43:02
>>> 0: cs:WFConnection st:Primary/Unknown ds:UpToDate/DUnknown C r---
>>> ns:0 nr:264 dw:520 dr:316 al:0 bm:2 lo:0 pe:0 ua:0 ap:0
>>> resync: used:0/31 hits:20 misses:2 starving:0 dirty:0 changed:2
>>> act_log: used:0/127 hits:25 misses:0 starving:0 dirty:0 changed:0
>>>
>>>
>>> Started drbd (no heartbeat) on hydrogen
>>> oxygen:~ # cat /proc/drbd
>>> version: 8.0.1 (api:86/proto:86)
>>> SVN Revision: 2784 build by root at oxygen, 2007-03-05 08:43:02
>>> 0: cs:StandAlone st:Primary/Unknown ds:UpToDate/DUnknown r---
>>> ns:0 nr:264 dw:520 dr:316 al:0 bm:2 lo:0 pe:0 ua:0 ap:0
>>> resync: used:0/31 hits:20 misses:2 starving:0 dirty:0 changed:2
>>> act_log: used:0/127 hits:25 misses:0 starving:0 dirty:0 changed:0
>>>
>>> On hydrogen, I'm seeing:
>>> hydrogen:~ # service drbd start
>>> Starting DRBD resources: [ d0 s0 n0 ].
>>> ..........
>>> ***************************************************************
>>> DRBD's startup script waits for the peer node(s) to appear.
>>> - In case this node was already a degraded cluster before the
>>> reboot the timeout is 0 seconds. [degr-wfc-timeout]
>>> - If the peer was available before the reboot the timeout will
>>> expire after 0 seconds. [wfc-timeout]
>>> (These values are for resource 'r0'; 0 sec -> wait forever)
>>> To abort waiting enter 'yes' [ 520]:
>>>
>>>
>>>
>>> So just starting drbd on hydrogen causes a split brain and oxygen, now
>>> the primary, to go into a standalone state. Why is that? The file
>>> system is mounted as a read only file system so no changes should be
>>> taking place. This is not a primary/primary setup so there is only one
>>> "active" node at a time. I was under the impression that the rebooting
>>> node, hydrogen, should see that it is out of date and become
>>> secondary, resync itself with the primary and stay in the secondary
>>> state until that is changed? Am I wrong?
>>>
>>> Both systems are identical:
>>> SLES 10
>>> kernel 2.6.16.27-0.9-bigsmp
>>> drbd 8.0.1 compiled from source
>>>
>>>
>>> Thanks ahead,
>>>
>>> David
>>>
>>>
>>> _______________________________________________
>>> drbd-user mailing list
>>> drbd-user at lists.linbit.com
>>> http://lists.linbit.com/mailman/listinfo/drbd-user
>>>
>>>     
>>
>>   
> Thanks for the response.  I'm currently using the settings you talk
> about (sorry, should have included this before):
>
> resource r0 {
>
>  protocol C;
>
>  net {
>    after-sb-0pri discard-younger-primary;
>    after-sb-1pri consensus;
>    after-sb-2pri disconnect;
>  }
>
>  syncer {
>    rate 120M;
>  }
>
>  on hydrogen {
>    device     /dev/drbd0;
>    disk       /dev/sda4;
>    address    172.16.0.2:7788;
>    meta-disk  /dev/sda3[0];
>  }
>
>  on oxygen {
>    device     /dev/drbd0;
>    disk       /dev/sda4;
>    address    172.16.0.1:7788;
>    meta-disk  /dev/sda3[0];
>  }
> }
> _______________________________________________
> drbd-user mailing list
> drbd-user at lists.linbit.com
> http://lists.linbit.com/mailman/listinfo/drbd-user
>

-- 
==============================================
Francesco Ciocchetti (francesco.ciocchetti at kyneste.com)

Network & Security
Kyneste - Piattaforme ICT
"Società appartenente al Gruppo Bancario Capitalia e
sottoposta all’attività di direzione e coordinamento di Capitalia S.p.A."
Via Mario Bianchini 68, 00142 Roma
T.[+39] 06.98402.1 F. [+39] 06.98402.300
http://www.kyneste.com/
==============================================

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