[DRBD-user] Dual-primary setup: disconnecting

Stephan Budach stephan.budach at jvm.de
Fri Mar 22 17:43:02 CET 2013

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

Am 20.03.13 09:08, schrieb Adam Goryachev:

> Why not configure as dual primary, but configure the initiators to only
> talk to a single target, and only change to the other target after
> failure/timeout. I haven't done this yet, but it is my plan to implement
> it soon.
> It would be nice to hear whether this "should" work as expected.... Any
> comments?
> Regards,
> Adam

Well, from the practical side of things… I never had any issue even with 
multipathing, but that doesn't mean, that corruption could not occur, of 
course. It is my understanding though that, if multipathd is configured 
for failover instead of multibus, the inititator would only ever use one 
path and only in case of a failure use the other one - well, just as the 
settings suggests.

However, if using multipathd in failover mode would be okay, then I'd 
like to revisit the top of this thread, where DRBD got hiccups when I 
did exactly this. While pumping data from three initiators, I suddenly 
got that timeout on one host that lead to these immediate 
disconnects/reconnects, which obviously didn't harm anything, but 
flatlined the performance on either host.


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