[EMAIL PROTECTED] wrote: > >Robbert Haarman writes: >> Greg, >> >> Again, you raise some interesting issues. I >wonder how likely the >> catastrophic failures you describe are, versus >how likely it is that >> things fail in a way where ccd actually helps >you. I was hoping someone >> else would comment on that, but that doesn't seem >to have happened so >> far. > >When you do a "shutdown -r", has the system ever >hung on you? Has >your system ever crashed/paniced/suffered a power >outage? > >How does ccd guarantee that the mirrors are in >sync? If it can't do >that, then it's worse than using just a single >disk, because a fsck >is only going to look at one half of the mirror, >and inconsistent >data on the other half is not going to be touched. >
Thankee. Now it makes sense. It is rather WORSE than you paint. Once there is ANY discrepancy between the disks, Murphy's Law is operable and Mother Nature will deal you its choice of which sector, when. The disk you update is not the disk fsck'd. The system seeming to run properly is no assurance that it can continue to do so. Disk cache and all that. Looks like the only safe way to come up after a power fail is to break the mirror, fsck, and re-mirror. Hardware might know which if any disk had not been updated.
