[DRBD-user] drbd with heartbeat won't fail over

[Lars Ellenberg]

On Mon, Jun 18, 2007 at 10:07:08AM -0400, Dan Gahlinger wrote:
> stonith won't help with what we're trying to test.
> 
> using both communications channels seems it won't solve this issue either.
> 
> we wan't heartbeat to fail drbd over if the main (or "public") interface is
> down.
> the machine may still be operational, but the network could be down - for a
> number of reasons.

thats what the "ping nodes" are for.

> if we monitor both communications channels as you say, it'll never fail over
> because the cross-over cable
> for the drbd data never fails.

the main point of having multiple comm channels is not to
"monitor" the single channel,
but to provide redundant communications.
 (-> read up on split brain, and why you want to avoid it)

> we currently have heartbeat monitoring the "public" ip of the other server.
> we can't have the drbd data on the same interface - because that could end
> up being too much traffic
> and would limit our bandwidth to do any real work.

you are misunderstanding the main purpose of the heartbeats here.

> monitoring the cross-over (drbd) link is equally pointless. drbd manages
> that itself quite well.

see above.

> if we disable heartbeat for drbd monitoring, then we lack the ability to
> umount and remount the partitions if servers fail.

huh?

> it seems that in this instance heartbeat can only be used for a full server
> failure (lost power).

read up on the concept of "ping nodes".


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: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
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