[DRBD-user] How to make a data backup on the secondary node?

Florian Haas florian.haas at linbit.com
Wed Nov 7 19:03:19 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.

On Wednesday 07 November 2007 16:50:49 Leroy van Logchem wrote:
> Dominik Klein wrote:
> > drbdadm primary $res
> It's not supported to do this safely. But if you really want it, try it
> without going primary.
> If it's ext2/ext3 you don't have to mount the file system, just dump to
> file. Otherwise mount -o ro.

Leroy, try accessing a Secondary DRBD in any way, dump, mount read-only, 
whatever, and if it succeeds, 2 pints are on me. :-)

Dominik, what you are attempting to do is possible by way of temporarily 
suspending redundancy on your cluster. And deliberately inducing split brain. 
If something goes wrong on your Primary in the meantime, you will not be able 
to avoid a service interruption. If you're held liable for that, don't come 
whining. If you're not scared yet, read up here for inspiration: 

This will also tell you why a full resync is *not* necessary afterwards, 
contrary to your earlier observation. :-)


: Florian G. Haas
: LINBIT Information Technologies GmbH
: Vivenotgasse 48, A-1120 Vienna, Austria

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