On Fri, Mar 30, 2007 at 11:13:48AM +0200, Max Hofer wrote: > On Thursday 29 March 2007 22:32, Dejan Muhamedagic wrote: > > 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 > > > 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. > My problem with this solution that i do not use the action-serialzing effect > of the transition engine.
I don't really get this one. > > > 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. > This is out of question because i can not interconnect all nodes to each > other with a serial cable or with a directy LAN cable. You could use a switch in case there are no security issues. I'm afraid that they really have to be able to talk to 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. > This is already on place - resource location constraints based on node names. > > > > 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. > My idea was A2 is attached to the LAN and the CIB change from B1/B2 > is propagated to A2. Then A2 propagates this change over the serical cable > to A1. CIB changes are always propagated. But all nodes have to be connected. > Maybe i really do not need this scenario and I probably just move all > mobile resources of cluster A from from A1 to A2. Hmm, don't understand this one either. What's a mobile resource? > I just wanted to know how this scenraio is handled by the heartbeat > framework. Probably not very well. > > kind regards > Max -- Dejan _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
