death by swap

When I was running our 60 desktop XDMCP/NX server on 12GB of memory, performance was
fine even though swap space usage was usually 8+ GB. We ran this way for months with no
complaints. Just because you're using a lot of swap space doesn't mean you are paging
excessively. Note that if a page is paged out and then brought back into memory, it stays
written in swap to save writting it again if that page gets pages out again. You can't tell a
whole lot about how much swap you are *really* using by looking at the swap used number.
systat monitoring and sar -W are more useful than the swap used number for accessing
swapping.

I do use the twice ram rule. I'd rather the system get slow than crash or have the OOM
running loose on it.