I didn't see any other answers, so I'll take a shot... On Mon, Feb 02, 2004 at 03:44:57PM -0800, Louis Erickson wrote: [snip] > We've got a raid 5 with three drives. I'll spare you the comedy of errors > and/or sob story that you've all probably heard before, but the upshot is > that we have two failed drives and no current backup. > > When the second drive failed, the raid went offline right away. The > second failure was apparently due to a write fail on the disk. I presume > that the data on the second failed drive and the main drive is mostly in > synch, except for the last change made. My conclusion is that other than > the file being written, the rest of the data should be okay. Please tell > me if I'm wrong there. That's a reasonable guess, I think. It depends to some extent what went bad... once I had a drive that developed a few bad sectors, but the bad sectors were in the middle of the inodes for my /home partition, so it did some pretty serious damage. > We got identical drives to the one good drive and the second > failure, and have used dd to copy the data on to those volumes, so > we can attempt to recover and not hurt our only copies of this data. > I've seen another message on this list which suggests this should > work. Copies were made with no errors. > > At the moment, my system is a little old and does not have mdadm on it. > Is it worth getting and installing this, or am I best to stick with the > original raidtools? > I advise you to get and install mdadm -- it has worked fine for me and mdadm seems to be the overwhelming preference of the posters to this list and thus easier to get support for. > The question of the hour is: How do I get the two drives to come back > on-line in degraded mode? They have different event counters and will not > come up. > > Any advice or direction you can provide will be very much appreciated. Once you have mdadm, mdadm --assemble /dev/md<whatever> --force <good drive #1> <good drive #2> missing should work for you. Note that "missing" is a literal string which you supply instead of a third device name, indicating that you want to assemble a three-drive array in degraded mode without one of its drives. You should see some message in the logs about forcing the event count of some drive or another. "--force" is necessary because the remaining drives' event counts are different. -Steve - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
