> OCFS2 is a shared-disk filesystem, and in EC2 neither ephemeral storage > nor EBS can be mounted on more than one instance simultaneously. > Therefore, you'd need something to provide a shared-disk abstraction > within an AZ. ?DRBD mode can do this, and I think it's even reentrant so > that the devices created this way can themselves be used as components > for the inter-AZ-replication devices, but active/active mode isn't > recommended and I don't think you can connect more than two nodes this > way. What I am doing is using DRBD for shared disk between AZs, which (with OCFS2) then gives me a standard POSIX file system, which I can share inside the AZ with GlusterFS. A bit of a duct-tape job perhaps, but seems like it will work. The proof will be in the testing, which I am just building instances for now.
