[DRBD-user] split brain - why does it not work out?

Raoul Bhatia [IPAX] r.bhatia at ipax.at
Thu Oct 16 14:29:42 CEST 2008

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

Florian Haas wrote:
>> To resolve split brain, I usually try the following:
>> 1- Disconnect both resources on both nodes (i.e. drbdadm disconnect resource)
>> 2- Mark both nodes as secondary
> Not necessary; you need to do this only on one node (the one you
> designate as your split brain victim).
>> 3- on the node you want as your primary do: drbdadm -- --overwrite-data-of-peer primary resource
> No, no, no, NO. You don't use this when resolving split brain.
>> OR
>> On the actual secondary do: drbadm -- --discard-my-data connect resource
> Better.

thank you - i was about to write something similar :)

>> This should "most of the time" prevent split brains....
> This does not prevent split brain. At all. This _recovers_ from split
> brain. What you do to prevent split brain is to use either
> resource-level or node level fencing (i.e. dopd or -- if you don't like
> dopd -- STONITH).

dopd and stonith are both running. stonith would not prevent this issue
as it is the direct result from a hard-reset. i would "expect" dopd to
fix this but somehow it did not. is dopd periodically trying to outdate
the peer, or only once?

DI (FH) Raoul Bhatia M.Sc.          email.          r.bhatia at ipax.at
Technischer Leiter

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