How can i reduce filesystem latency[system level]........

Filesystem latency may come from any of the following:

• Disk I/O wait: This may be as short as zero, in the event of a read cache hit. For a synchronous I/O event, this can be reduced by restructuring disk storage or by altering caching parameters. Disk I/O wait can be monitored directly through dtrace, including through the iowait.d script.
• Filesystem cache misses: These include block, buffer, metadata and name lookup caches. These may be adjustable by increasing the size of the relevant caches.
• I/Os being broken into multiple pieces, incurring the penalty of addtional operations. This may be a result of the maximum cluster size for the filesystem or the OS.
• Filesystem locking: Most filesystems have per-file reader/writer locks. This can be most significant when there is a large file (like a database file) where reads have to wait for writes to a different portion of the file. Direct I/O is a mechanism for bypassing this limitation.

Still i am working on it with practical issues.