3.7.0 HP StorageWorks HP Scalable NAS File Serving Software administration guide - HP Scalable NAS 3.7 for Linux (AG513-96002, October 2009)

Persist: This option causes the filesystem to be remounted automatically when the
server is rebooted and is enabled by default. If you do not want the filesystem to be
remounted automatically, remove the checkmark.
Create Directory: If you want HP Scalable NAS to create the directory mountpoint
on each server where the filesystem is to be mounted, click Create Directory.
Select any other mount options for the filesystem.
Async or Sync. Async, the default, allows either asychronous or synchronous I/O to
the filesystem. Sync allows only synchronous I/O.
Dev or NoDev. Interpret (or do not interpret) character or block special devices on
the filesystem. Dev is the default.
Exec or NoExec. Permit (or do not permit) the execution of binaries on the mounted
filesystem. Exec is the default. Noexec can be used on a system that has filesystems
containing binaries for other architectures.
SUID or NOSUID. Allow (or do not allow) set-user-id bits and set-group-id bits to take
effect. SUID is the default.
Std. File Optimized or DB Optimized. The Std. File Optimized option is the default
and optimizes file access for standard files. The DB Optimized option is intended
primarily for database files. This option bypasses filesystem I/O buffering, allowing
disk transfers to occur directly in application buffers. In database server terms, this
means the I/O will only be buffered in the address space of the database server
processes. For example, with the Oracle releases supported with HP Scalable NAS,
I/O will be buffered in the SGA or PGA. This eliminates the “double-buffering”
overhead associated with traditional filesystems.
Buffering directly in database server buffers also improves CPU utilization because
I/O buffers do not need to be copied from Kernel space to database server buffers.
Also, filesystem file data operations are not serialized, allowing multiple reads and
writes at the same time to the same file from multiple processes. This allows
applications to manage their own file data coherency (e.g., databases) to operate
more efficiently. (The coherency of metadata, or structural, operations continues to
be managed by the PSFS filesystem.)
To take advantage of the DB Optimized performance optimization, an application’s
read or write buffer argument to the read or write system call must be page-aligned
and must be at least a multiple of 512 bytes in length. Additionally, the target file
address (the offset from the beginning of the file where the I/O will start) must also
be a multiple of 512 bytes. If a transfer does not meet these three requirements, it
will be slower. Applications such as databases that support the use of raw partitions
always follow these constraints.
Configure PSFS filesystems134