I am trying to find out how many peek active process a server run in a 
given time period, like in one day, and may be a week. I try to see how 
servers handle heavy peak at time.

I thought that systat vmstat, or others could provide me that.

Unless I don't read the right man page, looks like the peak active stats 
process are not kept anywhere.

Is that the case, or is there a way to find more long term stats like that?

man systat talk about boot stats:

The following commands are specific to the vmstat and ifstat displays;
the minimum unambiguous prefix may be supplied.

boot    Display cumulative statistics since the system was booted.
run     Display statistics as a running total from the point this 
command is given.
time    Display statistics averaged over the refresh interval (the de- 
fault).
zero    Reset running statistics to zero.

But looks like I am not using it properly.

Any more informations available someplace that cold help?

Thanks

Daniel