RE: 64 node Oracle RAC Cluster (The reality of...)

 >
>Because CFS might not be the best fit for a myriad of small
>files that need to be paged into the memory quickly. CFS may
>not support anything but direct I/O, therefore not caching
>$ORACLE_HOME/bin/oracle and shared libraries on

this is not true for a real CFS. A proxy-cfs or nfs exhibits the characteristics you fear, but not a fully symmetric, concurrent read:write CFS. Demand paging is nothing more than the internals of mmap which in turn is really nothing more than an IO. Oh, with one exception, it is entirely 100% read only (a major text fault that is). That concern is a red herring. Binaries execute just fine from a CFS.

>$ORACLE_HOME/lib, which means that almost all page faults will
>be hard faults. On the other hand, if CFS does cache files as
>is the case with UFS by SUN Microsystems, it needs the same
>type of mechanism to synchronize the caches across the nodes
>as are the ones used by oracle. That might perform well only
>if background_dump_dest, user_dump_dest and core_dump_dest are
>not on the same global file system. Also, resist temptation to
>put archive destinations on CFS. Putting it on normal FS and
>then sharing it over public connection by NFS is much faster
>then by putting it on CFS.
>--
>Mladen Gogala
>Oracle DBA
>
>
>

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