3.7.0 HP StorageWorks HP Scalable NAS File Serving Software provisioning guide for Oracle HP Scalable NAS (AG513-96013, October 2009)

ORACLE_HOME will not saturate a cluster NAS head. Availability will not be
compromised, as failover and rehosting are certainly functional on filesystems
presented through a single VNFS.
Configuring NLM for Oracle Home
NLM is the locking protocol used by NFS. When Real Application Clusters is not
being used, Oracle uses file locks on a file in $ORACLE_HOME/dbs called
lk<DBNAME> to ensure that the database is not already opened by another instance.
NLM is disabled by default on FS Option for Linux. To enable NLM, simply log in to
each NAS head and execute the following command:
mxnlmconfig –e
For more information about this command, see the HP Scalable NAS File Serving
Software administration guide.
Best practices for consistent user and group ids
The ownership permissions across shared filesystems are determined completely by
the uid or gids assigned to the files and directories. In terms of how permission is
determined, it does not matter which users or groups have been assigned those
identifiers, either on the client or the server systems.
To share filesystems such as $ORACLE_BASE, the Oracle owner (e.g., user “oracle”),
and therefore the user ids and the gids of Oracle owner groups such as “dba” or
“ oinstall”, must be consistent across all NFS clients utilizing the same $ORACLE_BASE.
There is no requirement to actually create the user or the groups on the NFS servers.
However, it is easy for Oracle uids and gids on the Oracle servers (nfs clients) to be
created inadvertently in an inconsistent manner.
Therefore, HP recommends that before any Oracle install, the management team
determine the uids and gids that will be used for any $ORACLE_BASE. Assuming
your security policies allow this, if you additionally create these users and groups on
the NFS servers and preassign directory ownership to that user, you can block access
by incorrect user ids and group ids from your clients. Further, if the wrong identifiers
are used by root users to create a file or directory, it will be immediately obvious on
the NFS servers, since a listing of the directory on the NFS server will show the files
having ids as owners rather than a user as owner. If the NAS administrator assigns
the user Oracle as owner of the filesystems before they are mounted, anyone other
than user root using an Oracle id different from the predetermined id will be unable
to access the filesystem.
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