On Tue, 2011-01-18 at 07:27 +0000, Mick wrote: > On Tuesday 18 January 2011 04:42:38 William Kenworthy wrote: > > On Mon, 2011-01-17 at 16:23 -0800, Grant wrote: > > > And for those with gigabytes of swap, keep in mind that the majority of > > processors can only access up to 32 x 2G swapfiles under linux, so 4G is > > only going to be half used. > > Unless you are using your swap partition for hibernating to disk, when most > of > your memory in usage will be saved on it. In that case, if swap is less than > RAM, hibernation fails. > > BTW, it used to be that the kernel would not (easily?) access more than 128M > of swap for some reason and multiple 128M swap partitions were more efficient > than a single larger space, but this has probably changed with amd64 > processors and modern kernels.
Separate swapfiles of equal priority can be used (ala raid0) across multiple disks for a measurable performance boost The one big job I needed a large swapfile for (a clustalw alignment, which caused me to investigate swap usage) ran for nearly a month, generated ~46GB swap usage - and then generated a bus error and died. Developed hardware problems :( Two other areas I have needed insane swapfiles are humongous spreadsheets and graphics. More ram is always best, but sometimes its just not possible/available. BillK -- William Kenworthy <bi...@iinet.net.au> Home in Perth!
