Date: Fri, 7 May 1999 13:03:11 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Brian Feldman <green@unixhelp.org> Cc: Alfred Perlstein <bright@rush.net>, chris@calldei.com, "Ronald G. Minnich" <rminnich@acl.lanl.gov>, hackers@FreeBSD.ORG Subject: Re: memory-based VFS Message-ID: <199905072003.NAA46718@apollo.backplane.com> References: <Pine.BSF.4.10.9905071547530.93800-100000@janus.syracuse.net>
next in thread | previous in thread | raw e-mail | index | archive | help
:On Fri, 7 May 1999, Alfred Perlstein wrote: : :> On Fri, 7 May 1999, Chris Costello wrote: :> :> > On Fri, May 7, 1999, Ronald G. Minnich wrote: :> > > The v9fs memory-based VFS, written by Aaron Marks, is available at :> > > http://www.acl.lanl.gov/~rminnich/ :> > :> > Doesn't this do the same thing as MFS? :> :> Yes, but without the mount_mfs process kludge it seems to allow for :> single copy, rather than double copy and extra context switches, it :> uses kvm instead of a user process for backing store. : :So what would be wrong with using a swap-backed vn(4) and newfs/tunefs/ :mounting it? v9fs accomplishes a different purpose, as the author indicated. If all you want is a swap-backed filesystem then MFS or VN ( under current ) will work fine. MFS and VN both tie in at the device-block level. A real filesystem (UFS) must be emplaced above them. v9fs ties in at the VFS layer level. v9fs is not swap-backed ... what it is, really, is a fully-working demonstration project that people can build useful things on top of. Fully working demonstration projects are very cool things. People tend to build doubly cool things on top of them. I can see an immediate use for something like v9fs: a better devfs. Another futuristic cool use would be to make it the root filesystem with tie-ins from the loader. Add swap-backing and it could become a better union fs, or a more efficient swap-backed FS ( both MFS and VN can only partially recover swap space when files are deleted ). -Matt Matthew Dillon <dillon@backplane.com> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199905072003.NAA46718>