[DRBD-user] Refusing to be primary (outdated)

Lars Ellenberg lars.ellenberg at linbit.com
Wed Sep 26 00:08:57 CEST 2007

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

On Tue, Sep 25, 2007 at 02:56:36PM -0300, Luis F. V. Gomes wrote:
> Hi all
> I think this may have happened to one of yours but I could not find 
> any hints to solve this problem automatically in the archives:
> Due to a blackout, node 1 shuts down first and becomes outdated (DRBD 
> 8); node 2 acquires its resources and becomes primary for a few 
> minutes until it shuts down too.
> After power comes back, node 2 does not boot due to a hardware 
> transient problem (the disk is intact). Node 1 boots but refuses to 
> be primary because it is outdated and my clustered services (http and 
> email servers) are a joke.

to force a non-up2date (local data is outdated or inconsistent) drbd
to become Primary anyways, because you prefer to be online with
potentially stale data than to be completely offline,
 drbdadm -- --overwrite-data-of-peer primary all

but, yes, then you really forced drbd into UGLY mode,
diverging data sets and all, once you connect both nodes again
you will see some infamous "split brain detected" message,
and you'll have fun to sort out the mess.

provided that all important data on those boxes is actually
Maildirs, it may even be possible to merge it easily, though.

depending on exactly how "old" that "outdated" is,
this may be an option unless you prefer to fix the other node.

> Is there any configuration workaround for this situation?
> I just want the SMTP and POP services to wake up in node 1 (probably 
> using an alternative temporary spool directory) and later manually 
> resynchronize the data (maildir and queues) after fixing note 2.
> RedHat EL 5
> Heartbeat
> drbd.x86_64 8.0.3-1.el5.centos
> dovecot.x86_64 1.0-1.2.rc15.el5
> exim.x86_64 4.63-3.el5

good luck!

: Lars Ellenberg                            Tel +43-1-8178292-55 :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe    http://www.linbit.com :

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