On Wednesday 04 April 2007 15:35, Joe Morris (NTM) wrote: > dwain wrote: > > I am planning on adding a third hard drive to my mix. I will be > > buying 2 new larger ones, one for root and one for home and i would > > like to use the third one as a swap drive. > > Swap is typically 2x your RAM.
This is not a meaningful rule of thumb--it has nothing to do with anything real. If anything, having more physical RAM means you need less swap space to accommodate any given process mix. No matter how much RAM you have and no matter how much swap you configure, you'll hit a hard allocation limit (roughly RAM + Swap - Kernel), at which point programs' requests for more memory, attempts to fork a new process or attempts exec new programs will fail. So the real question is: How much virtual memory do you need during peak situations. Subtract from that the physical RAM size, add the fixed kernel memory requirements and that's how much swap you need. And, of course, any periods during which the working set (memory activately being accessed by running processes) exceeds physical memory (less kernel reserved memory) will be times during which thrashing results. When this happens, CPU utilization is low even though the load average is high and disk activity becomes nearly continuous and is dominated by paging traffic. Anything other than brief and transient occurrence of thrashing is usually intolerable. > ... > > -- > Joe Morris Randall Schulz -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
