On Friday 17 March 2006 00:35, "Mauro Mozzarelli" <mmkernel@xxxxxxxxxxxx> wrote: > >> > Incidentally such a large swap space will not do you any good in most > >> > usage scenarios. > >> > >> Three words: "suspend to disk". > > I use it for "tmpfs" There are situations where machines can perform very well with a tmpfs that is significantly larger than RAM. There was one time that one of my machines with 512M of RAM needed a 6G tmpfs and gave really good performance with 6G of swap. There are also some applications that have a working set which is far smaller than the full allocated memory space and which perform well when they are mostly swapped out. However I believe that neither is a common use of a machine. The general advice which is given as "use twice RAM" is something that I believe to be wrong in most instances now that machines with 512M of RAM or more are common. The issue of what size of swap space will be viable is really determined by the IO capacity of the storage device. Get a bunch of 15,000rpm SATA or SCSI disks in a RAID-5 array with a write-back disk controller and a swap space of several gigs in size may be viable for a wide range of work loads. Get a single IDE disk with a few gigs of swap and it's most likely that the performance of your machine will be unusable (to a degree that you have to press reset as logging in to run shutdown takes far too long) long before the swap space is fully used. I'm not trying to convince people that everyone should use less than 2*RAM for their swap space! Merely that the 2*RAM advice originated when 16M of RAM was a big machine and that things are different now. -- http://www.coker.com.au/selinux/ My NSA Security Enhanced Linux packages http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/~russell/ My home page -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
