File system performance tuning

There are many facets to file system performance tuning.

Sequential read performance tuning
The VMM sequential read-ahead feature can enhance the performance of programs that access large files sequentially.
Sequential and random write behind performance tuning
Write behind involves asynchronously writing modified pages in memory to disk after reaching a threshold rather than waiting for the syncd daemon to flush the pages to disk.
Asynchronous disk I/O performance tuning
If an application does a synchronous I/O operation, it must wait for the I/O to complete. In contrast, asynchronous I/O operations run in the background and do not block user applications. This improves performance, because I/O operations and applications processing can run simultaneously. Many applications, such as databases and file servers, take advantage of the ability to overlap processing and I/O.
File synchronization performance tuning
There are several ways to enhance file synchronization.
File system buffer tuning
The following ioo and vmstat -v parameters can be useful in detecting I/O buffer bottlenecks and tuning disk I/O:
Direct I/O tuning
The main benefit of direct I/O is to reduce CPU utilization for file reads and writes by eliminating the copy from the VMM file cache to the user buffer.

Parent topic: File system performance