Hi, i want to create a raid1 device via mdadm with only one hard disk device at the beginnig. Later, I want to add a second hard disk to this raid1 device. On the one side following command fails, when the second hard disk doesn't exist, even if I use the "--force" option: mdadm -C /dev/md0 -l raid1 -n 2 /dev/hda1 /dev/hdb1 On the other side, after using following command with one hard disk mdadm -C /dev/md0 -l raid1 --force -n 1 /dev/hda1 and following command after attaching the second hard disk mdadm -a /dev/md0 /dev/hdb1 then the second hard disk becomes only a spare disk. So my questions are: 1. How can I setup a raid1 device with only one valid disk with the intention to extend the raid1 device later with a second valid disk? 2. How can change a spare device to a active (raid1) device without recreating the raid1 md device? Thanks in advance. -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer