That is my point even mounting and dismounting filesystems is doable do we really want to do it working with a clustering software which does not know about filesystems except his own "filesystem" which is ASM? That is why I said ASM is a must if we want to use Oracle Clusterware to setup an active-passive cluster. Thanks -- LSC On Tue, Feb 23, 2010 at 7:08 PM, Mark W. Farnham <mwf@xxxxxxxx> wrote: > Most ports support a read only mount of a volume mounted read/write on > one node. The only wrinkle I’ve noticed is that the appearance of new > objects on the non-rw node may be slightly delayed. I’m uncertain of the > exact mechanism of this delay, and it may vary by port. > > > > An interesting application of this is mounting all the log directories > (both archived redo and diagnostic) as read only without the need for > clustering software at the file system level. (They still have to be > shareable volumes, of course). IF you’re not storing online redo in ASM this > can also be used for the online redo logs, but of course you need the > dbfiles multi-rw-able for any flavor of RAC. But this thread isn’t really > about RAC. > > > > Purely for the active-passive idea, this of course means you can tail files > on read mounted volumes and see the dying diagnostics from a crashed node > without waiting for some other node to start or waiting to mount the > volumes. Then you have the last messages at hand if you want to look at them > before you activate the passive node. This can save a lot of time if the > logs are telling you about, for example, media failure or some other issue > that will just be repeated on the passive node. > > > > Presumably the interest in this type of architecture is minimizing the time > until the applications are available on the passive node if the active node > is in some sort of failure, as well as for routine planned switchover for > preventive maintenance and just to prove it will work. > > > > <I wrote too much. I just wanted to introduce the notion about > non-corrupting read only mountablility even without a clustered file system; > David is absolutely correct you don’t want multiple concurrent rw mounts > without a clustered file system, even if you can trick the OS into doing it > for you.> > > > > mwf > ------------------------------ > > *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto: > oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *David Ballester > *Sent:* Monday, February 22, 2010 6:26 PM > *To:* LS Cheng > *Cc:* jcmiranda@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx > *Subject:* Re: active-pasive cluster in linux > > > > > > 2010/2/22 LS Cheng <exriscer@xxxxxxxxx> > > Hi > > You can use OCFS2 if you wish but basically you need some sort of Cluster > Filesystem or Volume Manager such as ASM. > > I dont mention OCFS2 because introducing two clustering software (OCFS2 and > CRS) for a Single instance Active Passive solution is a bit too much in my > opinion that is why I said you are forced to use ASM (runs on top of CRS). > > Thanks > > > > > Or not use ocfs2 or any cluster filesystem, the only node that needs to > have mounted the filesystems is the active one > > If you try to mount a non cluster filesystem in another node while is > mounted in a first one, the other node should answer 'partition used' or > something similar ( prevents corruption ) > > when switching from nodes, as part of the automatic process, one node > should umount and the other mount ( may be fsck first ) > > > Regards > > > D. > >