Date: Tue, 13 May 1997 08:32:52 -0400 From: "Kevin P. Neal" <kpneal@pobox.com> To: John Duncan <jddst19+@pitt.edu> Cc: yves@CC.McGill.CA, freebsd-hackers@FreeBSD.ORG Subject: Re: An idea, it is possibly good Message-ID: <1.5.4.32.19970513123252.008fefbc@mindspring.com>
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At 10:35 AM 5/12/97 -0400, John Duncan wrote: >Yves Lepage wrote: > >> here's an idea to enhance file systems's usefulness: virtual partitioning. http://dynamic.isdn.uiuc.edu/~roth/vps/ I got to that link via the Linux Project Map. There's a mailing list set up as well. It has Linux and BSD people on it. >> Let's say I have a FreeBSD system on one big partition. Virtual partititioning would >> allow me for example to 'reserve' space for specified directories (at mount time let's say). > >> Ideally, the reservations could be made/altered on a mounted file system, possibly >> using a remount with options. Not with FFS. LFS would be a better (perhaps not best) move. LFS doesn't work, but (if I'm not mistaken) John Dyson is rewriting it. >Hmm. Yes, but I'm recalling a couple of lines from my high school >code of conduct: > >13) Parents are asked to encourage their children to stay in school > and to help them not break the school code. > >14) Parents are also to encourage their children to partition their > disks in such a way that the minimum speed/space tradeoff > is attained, with regards to what will be stored on the disks. Well, yes, but who can tune this with a minimum of difficulty? >--- >I'd say that "virtual partitioning" is a good idea in as much as >it is speedy to resize and rehash, _but_, I'm not sure if it's >release-style material. Anyone with a backup tape can repartition a >disk to find a better spacetime relationship in a matter of hours, >and such drastic action probably only needs to be taken when the >circumstances are dire. So, for "freebsd the server", it seems >unnecessary when the entire disk can fit on one or two tapes, or in >the autoloader. Think about it. With a VPS/LVM/LSM (call it what you want) system, you can have 1) Resizable partitions 2) Partitions that span multiple disks. 3) Infrastructure that can be easily extended to do: a) Mirroring b) Striping c) Media perfection d) Cloning (a form of mirroring) When I say "Cloning", I'm referring to the ability to snapshot a partition. Another filesystem will then appear under a different mount point, and it will be mounted Read-Only. Backups can then be done to the clone, instead of the real, live filesystem. Imagine doing backups at high noon, without irritating any users -- or without having to stop your work on your desk machine. Imagine being able to have spare drives hooked up to a machine, and then when a user partition fills up you can just tack on more space -- no interuption in service. Or perhaps that mathematical program chewed up more space than you had anticipated, so you "grew" the filesystem onto another disk. The uses are infinite. >Such a package may be useful for the guy who is using "freebsd >the workstation", and he parts his disk such that he has a 300-meg >root, 50-meg var, and 2k user... Yeah, I think that this would >be good functionality. Well, yes. >It might be a good idea to stray the source tree into a genuine >server and workstation install, with the server version containing >more of the stuff in source and with many more customizable options, >self-compiling to handle certain variances when installed, and the >workstation arriving in an easily installable binary format, >with a separate cd of the source snapshot. Workstation users I think the eventual goal is to have as much in LKMs as possible, or perhaps some other system where unneeded/unwanted features don't consume memory. I think it's difficult to say that one feature is a "workstation" feature, and another is a "server" feature. In this particular case I don't think that the distinction can be made. Anyway, if you are really interested in this I suggest the VPS mailing list. It's been pretty beaten to death on this list. -- XCOMM Kevin P. Neal, Junior, Comp. Sci. - House of Retrocomputing XCOMM mailto:kpneal@pobox.com - http://www.pobox.com/~kpn/ XCOMM kpneal@eos.ncsu.edu Spoken by Keir Finlow-Bates: XCOMM "Good grief, I've just noticed I've typed in a rant. Sorry chaps!"
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