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Newsgroups: comp.unix.bsd.freebsd.misc Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!nntp.coast.net!news.kei.com!newsfeed.internetmci.com!EU.net!sun4nl!hgatenl.hobby.nl!compi.hobby.nl!plm From: plm@compi.hobby.nl (Peter Mutsaers) Subject: Re: 2 swap devices: does it make sense? X-Newsreader: Gnus v5.1 X-Attribution: PLM Sender: plm@compi.hobby.nl Lines: 22 Organization: My Unorganized Home Message-ID: <87ivi7xqtc.fsf@compi.hobby.nl> References: <87u41zetl7.fsf@compi.hobby.nl> <4denac$re@vulture.dmem.strath.ac.uk> In-Reply-To: nbc@vulture.dmem.strath.ac.uk's message of 15 Jan 1996 23:17:32 -0000 Date: Sat, 20 Jan 1996 07:34:22 GMT >> On 15 Jan 1996 23:17:32 -0000, nbc@vulture.dmem.strath.ac.uk (Neil >> Brendan Clark) said: NBC> Peter Mutsaers <plm@compi.hobby.nl> wrote: >> If I define 2 swap devices, each on a different disk, and I'm doing >> heavy disk I/O: will both swap devices be used by FreeBSD 2.1 to >> divide the disk I/O over the two disks? NBC> Swap devices are interleaved, so the answer is yes. How NBC> effective this strategy is would (I imagine) depend on your NBC> hard disks; for example, I am unsure how useful two IDE disks NBC> would be since CPU time is used by data transfers, but SCSI NBC> drives would give a definite improvement. At least, that is, if NBC> the world is a fair place ;-) I have SCSI and now with two swap devices I do notice improvement. But I see always that on the two partitions about the same amount is used, even when I'm doing a lot of I/O to /var which is on the first one. I would expect in this case that the swap device on the other disk is used more. Is this not supposed to be true? -- ______________________________________________________________________ Peter Mutsaers | Bunnik (Ut), | "Quod licet bovis, plm@compi.hobby.nl | the Netherlands | non licet Jovi."