From Larry Snyder on Thu, 22 Jul 1999
Hi Jim --
I was among five guests on a local computer call-in radio show this past Monday. We're all open-source/linux geeks as opposed to the usual topics dealt with. We managed to give away 10 copies of the CheapBytes RH6 CD, and handled almost all of the questions pretty well. Got one that threw me: What's the max swap on an x86 box? I was about to go into the 1.5-2X ram, until the caller said they had a P2-400 (X2) box with 2G of ram. Then I started drooling and wondering why they didn't just get an Alpha (personal preference).
The maximum swap file or partition under Linux is 128Mb (or is that actually 127Mb)?
[ I read somewhere recently that in 2.2 this is no longer a limiting factor. I stick by my guideline of having one swap volume per physical disk. -- Heather ]
You can have upto 16 active swaps (any combination of partitions and swap files).
However, the old guideline of 1.5 to 2 times physical RAM is horribly outdated. I'd recommend one or two 127Mb swap files at the most. Using two is not really for the extra swap space, but to provide kernel with a place to do load balancing, which it will do if you have separate swaps . Obviously for that to make any sense you need to put the swaps on separate spindles (physical hard disks) and preferably on different controllers as well.
I did a little digging on the kt site, and I can't remember where Jim Pick's site wound up. I know it varies depending on the kernel version. Can you get me a 2-3 line answer that I can give to the radio people so they can provide an answer?
Jim Pick got the name "kernelnotes.org" (so http://www.kernelnotes.org is the site formerly known as http://www.linuxhq.com). However, http://www.linuxhq.com does seem to be back up, with basically the same content. So, there's no real problem either way. (There is probably some interesting inside gossip regarding the whole affair, but the public statements seem to have all been mutually agreeable).
I hate leaving things hanging.