Date: Sun, 22 Feb 2004 13:16:22 +1030 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Lukas Ertl <le@FreeBSD.org> Cc: geom@FreeBSD.org Subject: Re: GEOM + RAID5 help Message-ID: <20040222024622.GM55671@wantadilla.lemis.com> In-Reply-To: <20040221162942.P19540@leelou.in.tern> References: <20040221162942.P19540@leelou.in.tern>
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--9v2bTOXBzuB5Piju Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Saturday, 21 February 2004 at 16:40:56 +0100, Lukas Ertl wrote: > Hi, > > I'm currently implementing the RAID5 bit of geom_vinum, and I could use a > little help. One problem I'm faced is that if the subdisk where the > original request should go to is down, I need to read all the other > stripes, recalculate the parity with the original data, and then write the > parity stripe (in the BIO_WRITE case), or read all other stripes plus the > parity to recalculate the desired data (in the BIO_READ case). You don't need to have a disk down to have this issue. When writing a RAID-5 block, you almost always need to do something similar. Look at complete_raid5_write() in vinuminterrupt.c for how it's done now. Greg -- Note: I discard all HTML mail unseen. Finger grog@FreeBSD.org for PGP public key. See complete headers for address and phone numbers. --9v2bTOXBzuB5Piju Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQFAOBf+IubykFB6QiMRAkSrAJ4sq0sJBFHCR6ASbNicqvGu0uj/0gCfUjxT 7hrOWe/6J4BnCXNSGgbPqZY= =eumt -----END PGP SIGNATURE----- --9v2bTOXBzuB5Piju--
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