Can anyone shed some light on vmstat in solaris ? I know It shows the amount of ram, page file and cpu useage etc but how can vmstat help me to fine tune the system performance ?

vmstat (Virtual Memory Statistics)

vmstat – vmstat displays virtual memory statistics of process, virtual memory, disk, trap, and CPU activity.

For system having mulitple CPUs, vmstat averages the number of CPUs into the output.

syntax
Basic syntax is: vmstat <interval> <count>

option – let you specify the type of information needed such as paging -p , cache -c ,.interrupt -i etc.

Without options, by default information about process , memory , paging , disk ,interrupts and cpu is displayed .

interval – is time period in seconds between two samples . vmstat 4 will give data at each 4 seconds interval.

count – is the number of times the data is needed . vmstat 4 5 will give data at 4 seconds interval 5 times.

Example
The following command displays a summary of what the system
is doing every five seconds.

example: vmstat 5

procs memory page disk faults cpu
r b w swap free re mf pi p fr de sr s0 s1 s2 s3 in sy cs us sy id
0 0 0 11456 4120 1 41 19 1 3 0 2 0 4 0 0 48 112 130 4 14 82
0 0 1 10132 4280 0 4 44 0 0 0 0 0 23 0 0 211 230 144 3 35 62
0 0 1 10132 4616 0 0 20 0 0 0 0 0 19 0 0 150 172 146 3 33 64
0 0 1 10132 5292 0 0 9 0 0 0 0 0 21 0 0 165 105 130 1 21 78

The fields of vmstat's display are
procs
r in run queue
b blocked for resources I/O, paging etc.
w swapped
memory (in Kbytes)
swap - amount of swap space currently available
free - size of the free list

page ( in units per second).
re page reclaims - see -S option for how this
mf minor faults - see -S option for how this
pi kilobytes paged in
po kilobytes paged out
fr kilobytes freed
de anticipated short-term memory shortfall (Kbytes)
sr pages scanned by clock algorithm
disk ( operations per second )
There are slots for up to four disks,
labeled with a single letter and number.
The letter indicates the type of disk
(s = SCSI, i = IPI, etc).
The number is the logical unit number.

faults
in (non clock) device interrupts
sy system calls
cs CPU context switches

cpu - breakdown of percentage usage of CPU time.
On multiprocessors this is an a
average across all processors.
us user time
sy system time
id idle time

By analyzing these parameters you can decide whether the load or memory usage is high on the server and you can do load balancing or other optimization techniques.

For any further information you can check my blogs: Solaris