On Thu, 11 Jan 2007 at 06.35.40 -0600, Dave Alitz wrote: > I'm starting with 4 drives. Two active in the current mirror and two > unused. The process I'm considering: > > Fail and remove a drive from the current md mirror, leaving three > unused drives > Create a new RAID5 array > Add the new md RAID5 device as a member of the degraded mirror RAID1 doesn't work the way you think it does. You'll end up with a degraded RAID1 made from a RAID5. It will work though. I recommend creating a degraded RAID5 from your two unused disks and doing a copy to the new array. After the data are copied, fail one disk out of the old array and add it to the new array, which will cause parity to be computed. After that's done, nuke the old array and add the last disk to the new array as a hot spare. This way, you end up with one array composed of physical disks, and your data are always in two places throughout the process. -- Sidney CAMMERESI http://www.cheesecake.org/sac/