Date: Tue, 18 Mar 2003 17:23:39 +1030 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Jeff Roberson <jroberson@chesapeake.net> Cc: Terry Lambert <tlambert2@mindspring.com>, Brooks Davis <brooks@one-eyed-alien.net>, Julian Elischer <julian@elischer.org>, Alfred Perlstein <bright@mu.org>, FreeBSD current users <current@FreeBSD.ORG>, fs@FreeBSD.ORG Subject: Software RAID caching? (was: Anyone working on fsck?) Message-ID: <20030318065339.GQ84879@wantadilla.lemis.com> In-Reply-To: <20030317230147.I66343-100000@mail.chesapeake.net> References: <3E769970.3A05ECAF@mindspring.com> <20030317230147.I66343-100000@mail.chesapeake.net>
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--uRjmd8ppyyws0Tml Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Monday, 17 March 2003 at 23:02:38 -0500, Jeff Roberson wrote: > On Mon, 17 Mar 2003, Terry Lambert wrote: > >> Jeff Roberson wrote: >>> On Mon, 17 Mar 2003, Brooks Davis wrote: >>>> I am still intrested in improvements to fsck since I'm planning to buy >>>> several systems with two 1.4TB IDE RAID5 arrays in them soon. >>> >>> For these types of systems doing a block caching layer with a prefetch >>> that understands how many spindles there are would be a huge benefit. >> >> I call that layer "Vinum" or "RAIDFrame", since that's a job I >> expect that code to do for me. 8-). > > They are not responsible for data caching. Only informing the upper > layers how many spindles they have. Software RAID should be a transform > only in my opinion. There is no reason to have duplicate block caches in > system memory. Agreed. Vinum doesn't cache. There is one case, though, where it could be argued that it's worthwhile, namely in RAID-[45] parity blocks. Greg -- See complete headers for address and phone numbers --uRjmd8ppyyws0Tml Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE+dsJzIubykFB6QiMRAnxRAKCchEJe3ef58LaGhKV3ryDQ2KWSuwCffM0d IDGm/1c4dUXxIubQoi4Uq90= =TNJT -----END PGP SIGNATURE----- --uRjmd8ppyyws0Tml-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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