HP ProLiant DL380G5-WSS 3.7.0 HP StorageWorks HP Scalable NAS File Serving Sof - Page 134

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. 134 Configure PSFS filesystems