I forget from whom I first learned about kSar, but I am in debt to that person once again. I first learned about it about a year ago, and it has been extremely useful whenever I am trying to debug system where I do not have access to trending graphs. kSar is an open source graphing tool for Linux, Mac OS X and Solaris sar output. Graphs can be generated and exported to many different formats (JPG, PNG, and even a PDF with all the graphs in it).
By simply copying a few files from /var/log/sa (at least that’s the default on Linux, and of course it does depend on sar being installed and running, but 95% of the time it is), running kSar and choosing the data file, you get beautiful graphs. Try it right now, it will take you less than 10 minutes. (Note, I have a Mac, and I know the client graphical program works on Linux/Unix/Solaris, but I have no clue if it works on Windows — there is a run.sh script, but it just calls a jar file, so I am pretty sure it will work on Windows.)
I copy the /var/log/sa/sar* files to my laptop, then cat them together (usually cd /path/to/sa, cat sar* > alldays), then run kSar and click “Data -> Load from text file”. It is just that simple.