I am in the process of deploying a two-node CentOS+Xen with iSCSI for live migration. The idea is to create a 600GB iSCSI lun, mount it on one of the servers and partition it with LVM. Each VM will have its own logical volume in the lun. I will do a vhchange -a y on the other server to activate the logical volumes. The question is: Am I going to need a clustered file system? (GFS2,OCFS) or its going to be fine? ALso, in case I add 2-3 more servers will this deployment still work or there is no way of doing it without a clustered file system? In each logical volume only one vm will write at the time and it will switch to another server only when it will migrate. I want to keep it as simple as possible, no RHCS or any other similar solution.



  • It has been two years since this question was asked. Does anyone have an update? Still not necessary to have a clustered FS? What are the current best practices for Xen + iSCSI + multiple hosts (and MPIO)? – Jed Daniels May 16 '11 at 23:18

No, you don't need a clustering filesystem, but you will need clustered LVM to manage the shared LVM metadata. If you really want to avoid that complexity, you'll need to put each VM in it's own LUN.


This article on Xen Live migration with Debian and iSCSI covers pretty much everything you need to do, though you might need to change a couple of paths, but the short answer is no you don't need a clustered filesystem with iSCSI, as it's a block-based protocol rather than a file-based one like CIFS or NFS.

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