Hello, i recently installed Centos 5 on a new server with a single scsii disk. After the installation, i added 2 additional disks that were once the components of a raid0 array on another server. I get some errors and am unable to start the array the following is an extract from dmesg output: md: Autodetecting RAID arrays. md: could not open unknown-block(8,17). md: could not open unknown-block(8,33). i then examined each disk in fdisk Device Boot Start End Blocks Id System /dev/sdb1 1 17501 17921008 fd Linux raid autodetect Device Boot Start End Blocks Id System /dev/sdc1 1 17501 17921008 fd Linux raid autodetect I tried to re-create the array and get this: mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1 mdadm: chunk size defaults to 64K mdadm: Cannot open /dev/sdb1: No such device or address mdadm: Cannot open /dev/sdc1: No such device or address mdadm: create aborted yet obviously the devices are there. what else should i look at. putting the drives back in the old server, and the array comes up with all data intact. Any ideas ? thanks, Michael ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.