K 10 svn:author V 6 dillon K 8 svn:date V 27 1999-09-23T09:25:05.000000Z K 7 svn:log V 731 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. END