On Thu, Mar 29, 2007 at 06:36:15PM +0200, Max Hofer wrote: > I have a questiuon regarding the heartbeat messgage exchange. > > Currently i have 2 cluster systems, each consisting of 2 node: > - cluster A consists of nodes A1, A2 > - cluster B consists of nodes B1, B2 > > All 4 nodes are attached with bonded interface to a tow LAN > switches SW1 and SW2 (lets call it normal LAN). > > A1 and A2 (and B1 and B2) have a direct interconnection where > the DRBD devices are syncronized plus a serial cable (lets call it > DRBD LAN) > > Thus currently cluster A (and B) use 3 different ways to exchange > the heartbeat packages: > - bcast ofer the DRDB LAN > - ucast using normal lan > - the serial cable > > Now i figured out the cluster A needs states/data from cluster B > (and vice versa) for some fail-over decisions.
Bad luck :-/ > I see 2 possible solutions: > a) wrting a resource agent which polls the state from the other cluster > and i use this state Interesting idea. Not sure how tricky it would be to do right. Depends also what for you would use that state. I guess to restart some resources. > b) i configure 1 single cib.xml with 2 "sub-clusters" This is an obvious solution, but probably you'd have to do some rewiring, i.e. all nodes should be equally well connected with each other. > With sub-cluster i mean certain resource run only on cluster A and other > resource run only on B. I don't think that we have such a thing. The only option which could be of help is to say that the cluster is asymmetrical, but that won't buy you much either. > My question now: > * what will happen if one of the nodes is disconnected from the normal > LAN - are the information tunnled over the redundant connections? > > Scenario: A1 is disconnected from SW1. A2 still recieves HB packages > via the serial line and the DRBD LAN. Do B1 and B2 see A1 as dead or > do the get the information about A1 via A2? I don't think a node can get info about another node through a third party. B1 and B2 will consider A1 gone. More, in this case, they'd be a majority and the cluster would go on and reconsider its options. > maybe strange scenario but i have it (but unfortunatly i can not test it out > because some external constraints .... managers! ;-) It is interesting, but could turn out to be a PITA. > kind regards Max > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems -- Dejan _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
