-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 18/04/12 01:12, NeilBrown wrote: > On Wed, 18 Apr 2012 00:42:54 +0200 John Crisp wrote: >> >> I don't understand how md1 shows [UUU] ?? > > You have a RAID1 with 3 devices. What it difficult to comprehend > about that. Probably a misunderstanding of the terminology - in Hicksville where I live mirrored usually just means a pair ;-) > Each block is written to all three devices. I didn't realise that a RAID 1 could have more than two devices. Most documentation around always illustrates a RAID 1 with a pair of drives and hence the confusion. > > You don't want that? Change it. > > mdadm --grow /dev/md1 --raid-disks=4 > > now it has 4 devices - though one will be missing. > Logical if you know it (RAID 1) can have more devices. > mdadm --grow /dev/md1 --raid-disks=2 Illogical naming if what you actually want to do is shrink the array............ like many things in life, once you know, you know. > > now it has 2 devices. Actually that won't work until you mark one > of the devices as failed, so > > mdadm /dev/md1 --fail /dev/sdc1 mdadm --grow /dev/md1 > --raid-disks=2 > And there lies the answer to my problem. For that I can't thank you enough ! > > But maybe you really wanted a 3-disk RAID1 before - it is a > configuration that certainly has a place. > No I didn't, but I now understand. > Next you'll be telling me that a RAID5 cannot be made with just 2 > devices! :-) Me ? I know jack ...... though I know one more thing than I did yesterday, and that is good enough for me ! Many thanks for the assistance. B. Rgds John -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPjn5zAAoJEPGW9QpGvPXME0sH/0p9dpJkZvWDDxP2sMjjDlE5 0xO8v3BY8frdHT803EYaQUkxOStgtkgMd8+MaZIK3M5Z8DM2BpbDuGyz39FvZ7Ai r+TWygB2lESxgnFI1PbSeZq+qZholIpS+TD8cJ25gDImXjD9mtkN8sx/cMmcVP7k CHzPY5cPOGCHNPC1V1BOYAU82+fjGZP8asQJT/TjUTQ/DlWuGVkDSENYGkWNY84T a7MuF40StY6/RG1X3ETiTlk/iq2+1j7V6I+tQlTIqWyREb9T82O2YJ2HzTeN5uN7 YXc/asVRjELmIQHode/Xq9WXkGZpQskdHqLAPyP1lKc1aNyKARsyaGHKvYZj/94= =a+Ob -----END PGP SIGNATURE----- -- 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
