> Say I had 2 hosts A & B, both have a scsi card ( id's 7 & 6 repectivly )
> and a scsi disk ( id 0 ).
>> This disk has a single filesystem on it.
>> Can host A mount the fs rw and host B mount it ro.
Not really. Host A will have a consistent view of the
fs, but Host B won't. It won't know when to invalidate stuff
that it's cached. Host A could serve the filesystem over
NFS, thus ensuring that all read access goes through Host A's
cache.
Right now, your best bet is probably the heartbeat project
at http://linux-ha.org. Every so often the mailing list
heads off into a discussion on shared disk handling, so
there is probably some info on these issues there.
In the long term, the Linux Cluster Cabal's VMS-like
clustering will be the way to go.
> If host A goes away for some reason ( crash etc ) can host B remount the
> fs rw or will much stuff break.
You'll need to use a journalling filesystem or you'll spend
ages fscking before you can safely remount.
Later,
Kenn
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