On Fri, 11 Sep 2009, Lamont Granquist wrote: > historically it used to be the case that to make use of any swap you > needed more swap than available RAM, and 2xRAM used to be the practice.
Hi Lamont. Some swap algorithms actually wouldn't work properly unless swap was at least double ram. No modern OS should act that way through. > then with virtual addressing of swap that became 1xRAM. with solaris i > believe that you still want to have some swap since it will OOM earlier if > it doesn't have any swap (its been years since i went through the details > of this and don't know if solaris 10 still goes OOM at the same > threshold). linux is extremely lazy, however, so it runs fine swapless. > > ( i belive the difference is that if you attempt to malloc some massive > amount of memory on solaris it will want to allocate some anon memory or > swap space even for the anon pages that aren't being used -- and when used > + allocated anon memory exceeds RAM + swap that solaris will OOM -- linux > is lazy and will just OOM once it actually can't get any pages ). It sounds like you're talking about memory overcommit. The behaviour of Linux is configurable but the default on modern systems is to do heuristic checking. http://www.linuxinsight.com/proc_sys_vm_overcommit_memory.html Cheers, Rob -- I tried to change the world but they had a no-return policy http://www.practicalsysadmin.com _______________________________________________ Discuss mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
