Les Mikesell spake the following on 9/29/2006 11:48 AM: > On Fri, 2006-09-29 at 13:23 -0500, rado wrote: >> so close yet so far or maybe that's just the way it is, I am dumb on it >> but gettin smarter. >> >> the 2 ide drives diff channels of course hda and hdc each w/3 partitions >> hda1 2 3 hdc1 2 3. >> >> I format hot add sda1 2 3 >> cat /proc/mdstat it's all there > > Unless you created it with 3 members, the 3rd is added as a spare. > >> ...# mdadm /dev/md0 1 2 -f /dev/hdc1 2 3 (fail or fault hdc >> >> md automatically picks up sda from spare status and writes to it. >> >> it finishes mind you hdc is still under fail status and I reboot. >> >> when the sys comes back up, it does not pick up sda anymore but instead >> just runs -U on all 3 partitions > > You can add /dev/hdc1 back if it didn't resync automatically. > >> I was under the impression that sda would be there either I missed a >> step somewhere or something strange going on > > I don't think usb/firewire is detected early enough to be included > in the raid assembly at bootup. That's why I set mine up to use > 2 internal drives all the time but only periodically sync to the > external drives that are then rotated offsite. And if you want to > be sure everything is clean on the copy, you should stop any > processes running on the mounted partition, and unmount the mount > point momentarily while you fail the disk. If you don't, the > contents would be the same as if the machine had crashed - probably > still usable, but it could have problems. > Maybe I am too far down the message tree to get this, but I don't see how taking one drive from a raid 5 array off site does any good. One drive on a mirror gives you a backup. One drive in a raid5 just gives you a used hard drive with not much possibility to recover anything. But feel free to slap some sense into me if I am too far off. I could see if you had a raid 5 array, and then mirrored that to a raid 1 with the usb drive opposite the "entire" raid5 array you would have a viable backup. But you could just as easily mount the drive and rsync to it to get the same effect. -- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!