-----Original Message----- From: linux-cluster-bounces@xxxxxxxxxx on behalf of Chris Picton Sent: Thu 1/3/2008 4:06 PM To: linux-cluster@xxxxxxxxxx Subject: GNBD/GFS/cluster questions Hi all I have a question regarding gnbd and clustering. I currently have two servers (store1 and store2) sharing a block device (/dev/sdc) via drbd. The 'Primary' server exports this device via gnbd, and the export fails over along with the drbd primary node. A third server (gfs1) imports the gnbd device (which is part of an lvm) and mounts a gfs2 filesystem on it. I currently do not want to run drbd in primary/primary mode, as I have read that there are potentially some performance issues with this. I have written two custom scripts to handle the drbd and gnbd resource failover. If I am not going to mount the gfs2 filesystem on store1, or store2, can I create a 'private' cluster between only those two machines, with their own dlm, or do all of the other machines (only gfs1 in this example) which will be mounting the gfs filesystem have to use the same dlm, and be part of the same cluster? If I were to share the drbd device via iscsi, then I see no need for the importing devices to even be aware that the device is being exported by a cluster of machines - does this hold true for gnbd as well? Is there any benefit of have *all* my servers in the same cluster, or can I split them up into smaller logically separated clusters. Eg, if I add another two servers, with a failover gnbd export, do they also have to be part of the same global cluster, if they will be sharing the gnbd device into the same clvm? Or can they have their own 'private' cluster between themselves as well? Regards Chris -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster I'm not an expert, as I have not used gnbd, but I would say you are correct. The two nodes that export, and do not mount, do not need to be a part of the gfs cluster - and really probably should not be. Thay can simply be their own active/passive failover cluster. Another 2 nodes, that export a different volume for the gfs cluster to use should be fine as well. Think of the pairs of gnbd nodes as two slices of an array. -C -C
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