Date: Tue, 7 Jun 2005 21:40:05 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Ivan Voras <ivoras@fer.hr> Cc: hackers@freebsd.org, scottl@FreeBSD.org, phk@FreeBSD.org Subject: Re: Google SoC idea Message-ID: <20050607194005.GG837@darkness.comp.waw.pl> In-Reply-To: <42A475AB.6020808@fer.hr>
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[-- Attachment #1 --] On Mon, Jun 06, 2005 at 06:11:23PM +0200, Ivan Voras wrote: +> I have an idea that I could implement through Google's "Summer of Code" +> project, but as I have little experience with stuff it involves (kernel +> programming / disks / filesystem optimization), so I expect any answer +> from "It won't work" or "It's useless" to "It can't be done". :) +> +> The idea is this: to implement sort of GEOM-layer disk data journaling +> system. I imagine it to be a GEOM class using two "lower-level" devices: +> one for data and one for the "journal" (this way, the journal device can +> be on a fast and small disk). Such journaled device could be used to +> host any filesystem, probably mounted with synchronoues-access, and it +> will result in faster write access by keeping the writes sequential in +> the "journal" device. Journal information will be commited to the data +> disk periodically by a separate log-writer thread, or when it gets full. +> The "data disk" will be consistent so it can be used without it's +> "journal" part (after a clean disconnect/rebuild) if needed. At the +> worst case, I think this will help performance in cases when there's a +> burst of write activity followed by a period of IO idleness. +> +> I've made the above idea more-or-less from my head in one afternoon, so +> it's perfectly possible that I'm missing some vital point or that it's +> complete nonsense :) +> +> Does it make sense to do it this way? Is it worth applying for the SoC? Not sure. Basically this is simlar what softupdate does, I think. From another point of view softupdates are only available for UFS. You probably wants to hear scottl and phk opinions (CCed). -- Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFCpfgVForvXbEpPzQRAulyAKDRdFAB5RebkoghErbCJRqidowyCgCg6j/V Inrlfvv6F5+Hwq+VvjImM4Y= =wc9J -----END PGP SIGNATURE-----help
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