Tech-Info: Important update on NFS mount options for Oracle

Dear SuSE customers,

We discovered two issues that we would like to inform you about:
- Customer complaint about Oracle error "no locks available" when 
keeping the database files in an NFS mounted directory
- Serious error in our "Oracle 9iR2 RAC on SLES-8 using NFS (Netapp)" 
document (NFS mount options).

Short:
- Single instance Oracle: use option "nolock"
- RAC: use option "noac" but NOT "nolock"


Unfortunately our RAC-NFS document mentioned above DOES include 
"nolock", which is wrong!


Best regards,
Michael Hasenstein



PS: Please also refer to http://www.netapp.com/tech_library/3183.html:

"... For some servers or applications, it is necessary to prevent the 
Linux NFS client from sending Network Lock Manager requests. You can use 
the "nolock" mount option to prevent the Linux NFS client from notifying 
the server's lock manager when an application locks a file. Note, 
however, that the client still uses more restrictive write back 
semantics when a file lock is in effect. The client always flushes all 
pending writes whenever an application locks or unlocks a file. ..."

This means the NFS client keeps the lock locally but does not attempt to 
inform the NFS server, and this way the lock works for single-instance 
databases.