On Sat, Sep 01, 2007 at 02:57:48AM +0200, Claudio Tassini wrote: > Hi, > I recently upgraded a 2-nodes cluster adding two more nodes. I would like a > single node to remain in cluster even if the other three are out of service, > so I'm trying to add a quorum disk to the cluster. > > The problem is that the quorum disk is a LUN in a shared storage which has > not the same device name through all the cluster nodes. Moreover, we use > device-mapper AND lvm. I could resolve the problem using an lvm logical > volume, because it would always have the same name and recognize the > underlying "dm" or "sd" device name even if it changes across a reboot, but > I've read that it's not advisable to use a logical volume as quorum device. You can do it, but if the LVM volume is clustered, you can introduce a circular dependency: * need quorum to access CLVM volume * need CLVM volume to become quorate... You can work around this by making qdisk's votes 1 less than the number of nodes in the cluster. Ex: 1 vote for qdisk and 1 vote per node, expected_votes = 3 & two_node = 0 for CMAN. Then, both nodes can come online before you start qdisk to eliminate the "chicken and egg" problem. This might also be related - There's a bugzilla open against qdisk; as qdisk doesn't work with devices which do not have a 512 byte sector size. I should have a fix for it this week. https://bugzilla.redhat.com/show_bug.cgi?id=272861 -- Lon Hohberger - Software Engineer - Red Hat, Inc. -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
