[Ocfs-users] Sharing a SAN

Jeremy Schneider jer1887 at asugroup.com
Fri Mar 12 14:52:03 CST 2004

We're running a configuration similar to that (but not quite as big). 
We have 2-Node RAC/1-Node AppTier for PROD and another 2-Node RAC/1-Node
AppTier for TEST.

I definitely wouldn't use OCFS for shared APPL_TOP's; OCFS is only
supported for DB files right now.  (The word on the street is that
they'll support regular files in ocfs2 though...)  But with RapidClone
it's rather trivial (at least compared to what it used to be) to just
clone the app tier and db tier filesystems between all the nodes.  Feel
free to send me an email off the list - we might be able to save some of
your DBA's a little time since we've documented all the steps to cloning
the 11i fileystems on RHEL.  In fact you can now (with 11.5.9)
install/clone the DB tier on the RAC nodes without even
installing/cloning the app tier and vice versa on the app nodes!  (Major
improvement over 11.5.8 where it was all or nothing with the

Personally I think you'll be less prone to problems if you don't try to
share the APPL_TOPs and ORACLE_HOMEs anyway.  It's closer to the default
configuration and will be easier to support and troubleshoot.  A few
extra steps when you add new nodes or want to refresh SUPP from PROD but
it's been worth it at our site.  Of course each implementation is
different and your case is certainly different from ours; maybe there
are some really good reasons you're looking into using shared

We have SUPP and PROD both on the same SAN in different access groups. 
No problems there at all.  Just be sure to take the time (if high
performance is important to you) and look at how the LUN's are spread
over the disks (try to reduce head contention) in the SAN and check the
paths from the servers to the SAN to make sure you're getting optimal
performance - the best performing apps are *designed* right the first

I don't know how many people are really running 11i on OCFS...  but
Oracle will definitely support it, and you absolutely can get superior
performance and availability by putting RAC on the backend.  Just make
sure you have a few smart, innovative DBA's and SysAdmins around in case
you hit any bumps.  As a word of encouragement, though, our
implementation has gone very smoothly - in fact we went live a few days
ahead of schedule.  (Except one major problem which I'm pretty sure just
got resolved and shouldn't affect anyone else once they release the next
update to OCFS).

Good luck,

>>> "Mark Harrington" <oracle01 at meharrington.com> 03/12/2004 2:04:56 PM
Hi All,

We are in the early stages of an Oracle E-Business Suite
running RHEL and are looking at different storage options.  For
we are looking at a 4-Node RAC/10-Node Application tier and a 2-Node
RAC/2-Node App tier for test.  We would like to use OCFS for both RACs
shared APPL_TOPs (an E-Business features that lets you share a single
of application code across multiple app servers) for the Applications

Can anyone see any issues related to OCFS or RAC (or anything else) if
had both TEST & PROD on one SAN segmented into 4 hard zones (PROD DB,
App, Test DB, Test App) all accessing a single disk array?

Is anyone else running a configuration similar to this?


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