Hi Jakov, I got your points , thanks a lot Regards Prathyush On Wed, Apr 3, 2013 at 11:16 PM, Jakov Sosic <jsosic@xxxxxxx> wrote: > On 03/22/2013 02:42 AM, Prathyush wrote: >> HI, >> >> >> I have 3 node cluster with 1 vote each ,and decided to shut down the 2 >> nodes for maintenance . >> When a proper power off /init 0 given to two of the nodes ,i never loses >> the quorum >> When i am making force power off (switching off the power/pulling >> the power cable) quorum was lost and services failed in the third node. >> why this is happening... any idea > > That's the exactly as should be. > > When you have 3 node cluster, and first node goes down - it's irrelevant > if it went down by standard shutdown or by pulling the cord, other two > nodes still have enough votes to hold the quorum. > > But now you're on just 2 out of 3 votes and things get a little bit more > complicated. > > If you shut down one of the remaining two nodes by standard shutdown > procedure, cman service will announce that the node is leaving cluster > (ccs_tool leave). > > Other node will now know that he's the only one left, and although it > won't have quorum, it will continue to provide services. It does not > have a reason not to, cluster was disassembled nicely. > > > But, if you pull out power out of one of the two remaining nodes, > simulating it's crash, it's OK for the remaining node to stop providing > services. He just doesn't know what's happening to other node, other > node could think the same and you would get split-brain scenario. > > One thing that could solve your problem is introduction of quorum disk, > which would hold 2 votes, so in the latter scenario, one node that > survives would make scsi reservation on quorum disk and would thus hold > 3 out of 5 votes. > > What kind of fencing are you using? Is it IPMI? > > -- > Linux-cluster mailing list > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster -- Regards, Prathyush -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
