Server replacement planning; performance monitoring
 

I have a few Linux (openSuSE) boxes that I'm planning to replace. Most likely, I'll consolidate a few of them onto one box, either with Xen or running multiple services on the same box.

Does anyone have any suggestions (specifically links to documents/HOWTOs/guides) that cover planning for system upgrades/replacement?

Specifically, I need to calculate the resources (processor speed, RAM, etc.) required on the new box(es).

I was thinking, for starters, of a tool that I could run on each machine that would report best-case, worst-case, and average-case use of processor time, RAM, etc. specifically on a whole-system and process-by-process basis.

I.e. I want to analyze the data and come up with something like "Apache should have 256Mb RAM, and a processor approximately equal to the current one", or "MySQL will probably need twice the RAM and 1.5-2 times the processor speed, as it's using up way too much processor time now."

Thanks for any advice,
Jason

OK, as a first step I installed Munin (http://munin.projects.linpro.no/) on a few machines. It's a graphical trending system somewhat like Cacti, but it uses check plugins on each individual machine, and RUNS OUT OF THE BOX. No config, just drop the plugins in a directory and it checks them.

Took me about an hour to install, but now I have a pretty good picture of resource usage, and more importantly what's using what. I downloaded a plugin that gives CPU usage % by user, for a specified list of users, and also wrote one that does the same for memory.

Hopefully after a few days, I'll start to be able to piece together the picture from all of my machines and figure out what's going to be needed.