RAM question for everyone!

[Chris Snook]

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?!?
> 
> Your thoughts are appreciated.
> 
> Thanks
> Dan
> 

I've said it before, and I'll say it again: you should always* have a little bit 
of swap space.  Yes, things get slower when you start swapping, but Linux, 
unlike Windows, doesn't swap when it doesn't need to.  If you have swap space, 
then as soon as you start using it, the performance hit to the app that's 
dirtying pages like mad gives the kernel more opportunity to free up other 
memory, reducing the risk of OOM-kills or kernel OOM panics.  You don't need a 
lot, and in fact I generally don't recommend having a lot these days, but you 
really should have some.

-- Chris

*There are certain carefully-tuned exceptions to this, but if you have to ask, 
they don't apply to you.