iostat

Solaris 
1)IOSTAT:

The values to look from the iostat output  are:

• Reads/writes  per second (r/s , w/s)
• Percentage busy (%b)
• Service time (svc_t)

If a disk shows consistently high reads/writes along with , the percentage busy (%b) of the disks is greater than 5 percent, and the average service time  (svc_t) is greater than 30 milliseconds, then  one of the following action needs to be taken

1.)Tune the application to use disk i/o more efficiently  by modifying the disk queries and using available cache facilities of application servers .

2.) Spread the file system of the disk on to two or more disk  using disk striping feature of volume manager /disksuite  etc.

3.) Increase the system parameter values for  inode cache  , ufs_ninode ,  which is  Number of inodes to be held in memory. Inodes are cached globally (for UFS), not on a per-file system basis 

4.) Move the file system to another faster disk /controller  or replace existing disk/controller to a faster  one.