>> Its more how much i/o rather than the size. If you have a bunch of >> stuff swapped out, but it hardly ever needs to be swapped in, the >> impact will be low. >> >> Keep an eye on the use with vmstat; >> >> adam@rix ~ $ vmstat 5 >> procs -----------memory---------- ---swap-- -----io---- -system-- >> ----cpu---- >> r b swpd free buff cache si so bi bo in cs us >> sy id wa >> 0 0 56700 351244 79564 207848 0 0 3 3 11 7 1 >> 0 99 0 >> 0 0 56700 351244 79564 207848 0 0 0 8 52 27 0 >> 0 100 0 >> 0 0 56700 351244 79564 207848 0 0 0 0 45 14 0 >> 0 100 0 >> 0 0 56700 351244 79564 207848 0 0 0 0 47 17 0 >> 0 100 0 >> >> from the man page; >> Swap >> si: Amount of memory swapped in from disk (/s). >> so: Amount of memory swapped to disk (/s). >> >> > Exactly! My system is the same way. > > Right now I've got a 4GB system that's using 708MB swap. But vmstat > isn't showing any swap activity. Why? Because some processes that I'm > not aware about because I'm obviously not using, got swapped out a long > time ago, and Linux is using that reclaimed RAM to compile chromium ;) > > If/when I need part of that 708MB becomes active, Linux will swap it > back in in one short burst that I doubt that I'll even notice.
Then why not have a really big swap file? If swap is useful as a second layer of caching behind RAM, why doesn't everyone with some extra hard drive space have a 100GB swap file? - Grant
