From: Steve D. <st...@us...> - 2008-04-25 20:16:15
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Maximilian Wilhelm <ma...@rf...> wrote on 04/25/2008 01:15:48 PM: > Hi! > > I've set up a Xen-Cluster with two nodes sharing some SAN storage. > > I decided to use EVMS to cut on of the LUNs into pieces for the DomU > storage. So I put a CSM on the LUN devices, and some LVM stuff in > there. > > If I now reboot/poweroff one node for any reason, the /dev/evms/... > devices managent by CSM on the running node disappear, which is quite > bad as I cannot start Xen DomUs when one node failed. > > Is this intentional or can I do anything about that? > > I can't imagine any reason for this behaviour and would realy like to > be able to use the volumes if only one node is alive. > > Ciao > Max > -- > Follow the white penguin. Hi, Max. The EVMS CSM will not display any shared storage on a node if that node is not in the membership of the cluster. The reason is that if the node is not in the membership then the CSM cannot guarantee that the node can safely access the shared storage. Last I heard it was still undecided if a single node in a two node cluster can declare that it is part of the membership of the cluster. All that the node can determine is that it cannot talk to the other node. It doesn't know if it is the only one alive or if it lost its connection to the other node. If the other node is alive, which one is in the membership and which one is not? If both nodes are up but cannot talk to each other, neither one can declare that it is the one in the membership and that the other node isn't. The typical way to handle the scenario is to have the node declare itself as not being in the membership. This is the safe solution. I have heard that there are some implementations or scenarios that allow one node to have then membership, but I don't recall the specifics. If you want to check if your node is in the membership, run "evmsccm -l". The evmsccm command is used by EVMS to determine if a node is in the membership. The "-l" switch says to list the nodes in the membership. Hope this helps. Steve D. |