I have a Centos 6 x64 server, ASL quad core with 4 GB RAM.

I have not had warnings, but apache runs up to 18% peak usage when I get a 400 people online. Even with that many online, only apache uses a lot of RAM, mysql and everything else is really low use.

Do I need to go to 8GB?

/swap is not used never seen it used.

I think it seems enough, but wanted opinions. Load is always good it's never been an issue. It ran great with a dual core, but I got hold of a quad cheap so I changed.

If its recommended to go to 8GB, I assume I don't have to touch my /swap it's never used at all, as unless it's critical, I don't want to mess with my partitions, especially as it's RAID LVM and I just installed Centos 6

Thanks!

A better question is what is your PHP memory set to per thread? A high PHP memory might explain it better.

grep mem /etc/php.ini
; Maximum amount of memory a script may consume (128MB)
; http://www.php.net/manual/en/ini.core.p ... mory-limit
memory_limit = 128M
; If this parameter is set to Off, then memory leaks will not be shown (on
; http://www.php.net/manual/en/errorfunc. ... t-memleaks
report_memleaks = On
; enabled, registering these variables consumes CPU cycles and memory each time
; A default size of the shared memory segment
;sysvshm.init_mem = 10000

Something to remember about RAM is that Linux automatically uses as much RAM as possible. Even if your box sits idle most of the day, you'll still use most of your RAM as the OS tries to keep commonly used things in RAM. It's when swap gets high use (it will never be 0 either, so don't count that) that you need to worry. Sounds like your box is just fine.

Thanks!

I did think so but just wanted to ask.