Patrick Caulfield <mailto:pcaulfie@xxxxxxxxxx> wrote: > Bowie Bailey wrote: > > Graham Wood <mailto:gwood@xxxxxxxxxxxxxx> wrote: > > > > > > Can I just drop the "two_node" definition for a 3-node cluster > > > > to force it to keep running with only one node? > > > > > > If you're looking at GFS, then this arrangement is almost > > > definitely going to fry the data in the partition - which will > > > take the system down for you permanently. > > > > > > Imagine that the 3 nodes lose communication (but all three are > > > still running) - they're all going to reply the logs from the > > > other two, and then start writing to the shared filesystem as if > > > they were the only ones in the cluster. > > > > > > Which will corrupt the GFS very quickly. > > > > Isn't that what fencing is supposed to take care of? Maybe I'm not > > understanding how this all works together. > > No, because fencing has to be done by one of the cluster nodes. And > the cluster must be quorate to fence another node - otherwise it > could be an isolated node fencing the valid part. Ok, that makes sense. How does this work with a two-node cluster? > > What I will have is three nodes. Two that actively use the data in > > the shared storage and one node that handles backups. > > > > The backup node is not critical and could be down at any time for a > > number of reasons. I want to make sure that if the backup node is > > down and one of the other nodes crashes, that the one remaining > > node will continue to be able to access the data in the GFS. Is there a way to make my setup work the way I want? -- Bowie -- Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
