LAMP Memory Usage
The spreadsheet is at
Here is a how-to guide for this spreadsheet:
The yellow boxes are values you need to enter. Next to each of these is a Linux command you can use to get the appropriate value. I am using PHP APC for opcode caching so that all PHP code is cached all the time, thus lowering the apache2 per process RAM.
After entering the values for the 1st 21 rows, you should enter your guess for apache2 max clients and then look in row 34 for the min free RAM to make sure it is not negative.
If it's so complicated, I should suggest considering dropping Apache for something like nginx/lighttpd/litespeed/cherokee/etc that takes mots of the effort out of this…
Determining memory usage for lighttpd, for example, involves basically using the stock lighttpd config, deciding how many fcgi PHP processes you want (8 can probably handle anything most sites throw at it, at an estimated RAM usage of ~150MB), and then grab the MySQL sample config appropriate for your machine (probably my-medium.cnf?) and you're good to go.
Well, I can't view your spreadsheet (Excel 2007 doesn't read ODS, Google Documents spits out server errors, ironically ODS has very little support while Excel documents are widely supported)
Ok, I added an excel version.