Date: Thu, 23 Sep 1999 02:25:05 -0700 (PDT) From: Matt Dillon <dillon@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/dev/ccd ccd.c Message-ID: <199909230925.CAA56889@freefall.freebsd.org>
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dillon 1999/09/23 02:25:05 PDT
Modified files:
sys/dev/ccd ccd.c
Log:
Cleanup CCD quite a bit, including adding clarifying comments.
Enhance MIRROR code. Add a few more sanity checks and implement
a zone-based disk selector to make use of both disks when reading.
Also implement a read fail-over. If a read error occurs on one
disk, the I/O is retried on the other.
NOTE: CCD's mirroring support cannot deal with write errors properly
in regards to recovery, meaning that 'old' data under a write error may
be read non-deterministically if you reboot after a write error, and CCD
certainly cannot deal with a disk changeout. And it still can't. Use
vinum if you are really serious about mirroring. CCD basically just
implements a poor-man's mirror.
Revision Changes Path
1.61 +358 -148 src/sys/dev/ccd/ccd.c
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