Do you have a verifiable (as in from a knowledgeable source) reference for this? - it goes against a lot of what I found googling a year ago where swap size was dependent on CPU architecture (i.e., zeon/opteron/athlon etc), not 32/64bit.)
e.g., see "How large can my swap space be?" at "http://lissot.net/partition/partition-04.html#SwapSize"; "Currently, the maximum size of a swap partition is architecture-dependent. For i386, m68k, ARM and PowerPC, it is "officially" 2Gb. It is 128Gb on alpha, 1Gb on sparc, and 3Tb on sparc64. An opteron on the 2.6 kernel can write to a 16 Tb swap partition. For linux kernels 2.1 and earlier, the limit is 128Mb. The partition may be larger than 128 MB, but excess space is never used. If you want more than 128 MB of swap for a 2.1 and earlier kernel, you have to create multiple swap partitions (8 max). After 2.4, 32 swap areas are "officially" possible. See setting up swap for details." I think this is out of date but its repeated at a number of sites, however there does not seem to be anything other than rumour elsewhere for the latest info (i.e., somebody said ..." I can confirm that on my 32bit intel and amd systems I can create large, multigigabyte single swapfiles, but they will not use more than just under 2GB of them. Will have to revisit and test 64bit systems I think. BillK On Tue, 2011-01-18 at 11:05 -0800, kashani wrote: > On 1/17/2011 8:42 PM, William Kenworthy wrote: > > > > No swap contains pages from memory that have not been accessed for > > awhile so they can be stored elsewhere freeing ram for actual active > > pages. When they need to be accessed, they have to be swapped back in, > > and often something swapped back out to make room for it. > > > > 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. Some processors are only able to handle > > very small swapfiles, whilst amd opterons can handle very large ones. > > > > It does appear however that some distros (redhat and suse ?) have > > modified something to allow larger swap sizes on 64bit systems, but via > > google it seems very muddy at the moment. > > > > On my mostly 32bit systems its only the opterons (which are running > > 64bit systems) that can access more than 2G swap using gentoo-sources > > kernels when I tested late last year. > > > > BillK > > On a 32bit x86 Linux OS your swap file or swap partitions can have a > max size of 2GB. If you're using a kernel later than 2.4.10 you can have > 32 swap device and previous to that it was 8. With a 64bit Linux OS you > can have swap devices of 64GB each. > > kashani > -- William Kenworthy <[email protected]> Home in Perth!
