AIX JFS dual-mount

There is something called clvm (concurrent logical volume manager) for AIX which ships as part of HACMP (high availability clustering software). Its a combination of a kernel module and a user-mode locking deamon. It allows multiple systems to access the same volume groups in a twintail SCSI or multi-initiator SSA configuration. The lock managers on each machine communicate over TCP/IP.

According to the HACMP training class, clvm is seldom used and is reported to be slow. Most developers (ie Oracle) choose instead to roll their own locking solutions. I've never actually seen anyone use it myself -- outside of an exercise in the HACMP class that is. ;)

Christopher

Maybe the topic is a bit arbitrary here - but CLVM does _not_ support dual-mount configurations. Main reason: it has no interface to the two JFS's write caches... Its only intent was to facilitate multi-host access to raw devices, a la databases, but as you say...

Exactly.

The only multi-mount filesystem on AIX so far is the GPFS (General purpose filesystem) running on top of the RVSD (Recoverable Virtual Storage Disk) which only runs on an SP.

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