On Fri, 2009-01-23 at 16:26 +0000, Bryn M. Reeves wrote: > Alan Evans wrote: > > On Fri, Jan 23, 2009 at 7:43 AM, Dan Track <dan.track@xxxxxxxxx> wrote: > >> I was recently asked a question about how much RAM should there be > >> within a server given that the APP uses 8GB of Memory, should I buy > >> 10Gig of memory and have a small harddrive and no swap space? Would > >> this configuration allow everything in my OS to run from RAM and not > >> from swap? If this is the case then there's no need to ever create > >> swap, is there?!? > >> > >> Your thoughts are appreciated. > > > > This question, along with other recent discussion about swap, leads me > > to ask a question in response: Why is everyone so concerned about how > > to get away without swap? > > > > Hard drives are cheap. Why does your server with potentially 10GB > > (!!!) of RAM have a hard drive so small that you can't sacrifice a few > > GB for swap? > > I think many people aren't as concerned about sacrificing a bit of > disk space as much as they are concerned about the performance impacts > when the system begins to use the swap, especially for desktops. > > Linux will attempt to move old data that has not been referenced for > some time out to the swap device even when there is relatively little > pressure to do so. This is generally a win since we are better > utilising the physical memory of the system (storing more > frequently/recently used data in it) but it may lead to nasty delays > when the swapped-out data is needed again. > > This is more of a problem today than 15 years ago because of the ever > widening gulf between main memory speeds and (HD based) mass storage > speeds (or at least, seek times). > > As an example, try opening something in OpenOffice and then minimizing > it for a week. Even if the box was fairly quiet for that period, > chances are that much of OO's address space is now swapped out. > Clicking the window in the task bar will cause the system to churn for > a few seconds or more before the app returns to a usable state. > > Regards, > Bryn. > Yeah, but this problem can more-or-less be avoided by lowering /proc/sys/vm/swappiness. - Gilboa -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
