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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!news.mel.connect.com.au!munnari.OZ.AU!news.ecn.uoknor.edu!qns3.qns.com!imci4!newsfeed.internetmci.com!in2.uu.net!news.thepoint.net!news1!not-for-mail From: root@dyson.iquest.net (John S. Dyson) Subject: Re: MFS - Why? X-Nntp-Posting-Host: dyson.iquest.net Message-ID: <4orbhr$8t@dyson.iquest.net> Sender: news@iquest.net (News Admin) Organization: John S. Dyson's home machine References: <AEn4jRr0u3@qsar.chem.msu.su> <npX7tgO@quack.kfu.com> <833457338.26209.0@arg1.demon.co.uk> <nqcignn@quack.kfu.com> Date: Sun, 2 Jun 1996 06:15:23 GMT Lines: 30 In article <nqcignn@quack.kfu.com>, Nick Sayer <nsayer@quack.kfu.com> wrote: > >>You can use the vnode driver (see vnconfig(8)) to allow swapping into a >>regular file. It may not be quite as convenient as some other OSs, >>but it certainly solves the problem. > >How? Once you add a swap area you can't remove it. So you can't >prepare for a large job by adding temporary extra swap, do the work >and then remove and dispose of this extra swap. That would be the >only equivalent behavior. Solaris 2.x can do this, but FreeBSD can't. >And in any case this behavior is not automatic. > That is a significant limitation that Jordan has wanted for quite a while. After we settle down from the latest VM megacommit (super-fast fork times, and vastly improved exec times), I am going to do the swapon/swapoff thing correctly. The swapon of a vnode is pretty simple, but swapoff will require verification that there is enough swap space after the partition is removed, and paging-in/out of the data that resides on the old partition. No biggie, just will take a bit of time. It is really odd that this subject would come up again, just when I plan to implement it :-). > >Don't get me wrong -- I still prefer FreeBSD to the alternatives, >but not being able to 'swapoff' is a bit of a bummer. > Thanks for the vote of confidence :-)!!! John dyson@freebsd.org