Toasters,

Is anyone using clones of OCFS2 filesystems in an Oracle RAC environment? I am testing cloning database LUNs to present back to the same server in order to accomplish zero downtime backup and ease of file-level and LUN-level recovery. The problem I am running into is that the UUID of the OCFS2 filesystem is cloned into the new filesystem (as expected), which causes the OCFS2 daemons to refuse to mount an already mounted filesystem (even though it's really not). While it's possible to change the UUID on OCFS2, it cannot be changed until all filesystems sharing that UUID are unmounted (and there is no "force" option).

The only solutions I see so far are:

1) After the clone is taken, unmount the live database and change the UUID on the clone. Obviously this is probably not the wisest solution for high-availability databases.

2) Mount the clone on a Linux host not in this RAC environment. Any Linux host running the OFCS2 modules and on the SAN can be used. The post-processing by the DBA (copying the last ARC and control file) can be done via SCP to the mounted filesystem on the secondary host. autofs would also be a nice solution to enable access of the filesystem from the RAC environment. I'd rather not have to rely on a secondary server to accomplish this.

3) Edit the filesystem superblock of the clone to change the UUID. This is highly technical, but possible. If anyone has ever done this, let me know.

I ran into the same problem with ASM (which does not let you change the label at all), which led me to try out OCFS2. I'm curious as to how other people are accomplishing ZDB and having a clone of an RAC-enabled database mounted on the same server.

TIA,

Daniel

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