Can I change any AIX System paramerter for speeding the data Disk performance?
Currently it slows with writing operations.

Is it the only direct way to fix the question?


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:

Counters of blocked I/Os due to a shortage of buffers
The vmstat -v command displays counters of blocked I/Os due to a shortage of buffers in various kernel components. Here is part of an example of the vmstat –v output:
...
0 paging space I/Os blocked with no psbuf
2740 filesystem I/Os blocked with no fsbuf
0 external pager filesystem I/Os blocked with no fsbuf

...
The paging space I/Os blocked with no psbuf and the filesystem I/Os blocked with no fsbuf counters are incriminated whenever a bufstruct is unavailable and the VMM puts a thread on the VMM wait list. The external pager filesystem I/Os blocked with no fsbuf counter is incriminated whenever a bufstruct on an Enhanced JFS file system is unavailable
The numfsbufs parameter
If there are many simultaneous or large I/Os to a filesystem or if there are large sequential I/Os to a file system, it is possible that the I/Os might bottleneck at the file system level while waiting for bufstructs. You can increase the number of bufstructs per file system, known as numfsbufs, with the ioo command. The value takes effect only when a file system is mounted; so if you change the value, you must then unmount and mount the file system again. The default value for numfsbufs is currently 93 bufstructs per file system.