Linux

If it is 2 disk RAID 5 then it is an utter waste of time and explains the poor I/O performance, take the two disks and mirror one against the other instead.

It's real hard to tell how frequently you're monitoring your statistics and unless you're looking at them very frequently, say every 10 seconds or so, you don't get a lot of help from your data. I do know the default sampling rate for sar is one sample every 10 minutes which might have made sense 20 years ago when computers were a lot slower but make no sense today. When sar tells you your cpu is loaded at 20%, how do you know it wasn't 100% for 2 minutes and 0 for 8? Same holds for everything else.

Personally I find looking at a single number and saying this is the CPU or network loads, isn't all that helpful either since nothing is constant. I find seeing numbers every second or so over a period of time when problems exist are much more helpful, but that's me...

-mark