Even though i always prefer to use ASM for all aspects of database storage (database files, flash recovery area etc) when using oracle real application clusters, there might be rare cases where you want to mix and match ASM and ocfs2 for the same Rac database. A specific case that i came across was that the customer’s backup software did not support direct backups from rman to tape (Hence they need to backup to a file system and then backup the filesystem to tape).

It is supported to have the oracle database files on ASM and the oracle flash recovery area on OCFS2, if you have a requirement to do so. DBCA supports the creation of such a database (Where the database storage is on a ASM disk group and the Flash recovery area is on OCFS2). In the DBCA screen where you choose the location of the Flash recovery area, you will not be able to click on the <BROWSE> button and pick an OCFS2 mount point (because by default it only shows asm disk groups). However you can type the OCFS2 mount point into the field and dbca accepts it and configures it correctly. DBCA will actually keep (As it does with ASM) one copy of the control file and the second member of the redo log groups on the OCFS2 mount point.

I am not advocating that customers use this configuration, because of the obvious difference of performance charachteristics between ASM and OCFS2. If one wants to use such a configuration then they should consider creating additional asm disk groups to keep copies of the control files and online redo log’s (As opposed to keeping them on OCFS2).