(I see that other people have had this problem but not in the same situation as me. Mine is probably as simple as you can get). I'm learning about how to manage software raid by using loopback devices on a RHEL6 system (2.6.32-71.14.1.el6.i686). I create two loopback devices thusly: # dd if=/dev/zero of=file0 bs=1k count=100 100+0 records in 100+0 records out 102400 bytes (102 kB) copied, 0.000689998 s, 148 MB/s # cp file0 file1 # losetup /dev/loop0 file0 # losetup /dev/loop1 file1 I can create a RAID1 volume with no problems: # mdadm --create /dev/md0 --raid-device=2 --level=1 /dev/loop0 /dev/loop1 mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. However, doing the same thing but creating a RAID0 volume fails thusly: # dd if=/dev/zero of=file2 bs=1k count=100 100+0 records in 100+0 records out 102400 bytes (102 kB) copied, 0.000699377 s, 146 MB/s # cp file2 file3 # losetup /dev/loop2 file2 # losetup /dev/loop3 file3 # mdadm --create /dev/md1 --raid-device=2 --level=0 /dev/loop2 /dev/loop3 mdadm: Defaulting to version 1.2 metadata mdadm: ADD_NEW_DISK for /dev/loop2 failed: Invalid argument I don't understand what went wrong? Any ideas? Cordially, -- Jon Forrest Research Computing Support College of Chemistry 173 Tan Hall University of California Berkeley Berkeley, CA 94720-1460 510-643-1032 jlforrest@xxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
