RAM question for everyone!

[Gordon Messmer]

Dan Track wrote:
> I was recently asked a question about how much RAM should there be
> within a server given that the APP uses 8GB of Memory, should I buy
> 10Gig of memory and have a small harddrive and no swap space? Would
> this configuration allow everything in my OS to run from RAM and not
> from swap? If this is the case then there's no need to ever create
> swap, is there?!?

We just discussed this in the "Ideal swap partition size" thread.

If your application is 8GB, you need at least 16GB of address space in 
case the server attempts to call an external program.  When it does so, 
it will call fork().  While fork() will not copy all of the pages of a 
process under Linux, you do generally need to have the space available.

If you're going to run an 8GB database server, with 10GB of RAM, I would 
strongly recommend at least 10GB swap space.  You won't use it, but the 
system won't work reliably if it's missing.