Judging from your tar comment, you're expecting way more output than this from dmraid -rD:
root@ubuntu:~# dmraid -rD /dev/sdh: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sdg: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sdf: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sde: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sdd: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sdc: ddf1, ".ddf1_disks", GROUP, ok, 3906572288 sectors, data@ 0 /dev/sdb: sil, "sil_acagdccaeafe", stripe, ok, 117229312 sectors, data@ 0 /dev/sda: sil, "sil_acagdccaeafe", stripe, ok, 117229312 sectors, data@ 0 However, your guess is wrong. I bought this system only a couple of months ago, and Maverick was the first and only OS to become alive on it. The controller on which the SATAs are sitting 00:1f.2 SATA controller: Intel Corporation 82801JI (ICH10 Family) SATA AHCI Controller (prog-if 01 [AHCI 1.0]) is incapable of doing RAID6. In the BIOS the controller is in AHCI mode, and has, aside from some very short-lived experimenting, always been in AHCI mode. These drives were empty before, and have only been used as an mdadm RAID. I did however recreate it a couple of times fiddling with various tweaks (mostly stripsize & metadata versions) before settling on the current config. But each time I never used the assume-clean option or such, allowing the mdadm RAID6 to fully build before doing anything else with it. Also, this particular problem didn't occur on Maverick, and simply excluding ENV{ID_FS_TYPE}!="linux_raid*" in udev 'solves' it in Natty, indicating that at least udev/kernel are aware that this is actually a linux_raid instead of a FakeRAID one. As a side note, I never heard of DDF1 before, and it was actually you who told me it was a metadata format. So I never actually tweaked neither mdadm nor dmraid as far as to specify an apparently deprecated format. ** Attachment added: "dmraid -n /dev/sdc" https://bugs.launchpad.net/ubuntu/+source/dmraid/+bug/742145/+attachment/1942995/+files/dmraid-n -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/742145 Title: ddf1 format should be disabled in dmraid in favor of mdadm -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs