I had to replace two hard drives in my RAID1. After adding the two new partitions the old ones are still showing up as removed while the new ones are only added as spare. I've had no luck removing the partitions marked as removed. Here's the RAID in question. Note the two devices (0 and 1) with state removed. $ mdadm --detail /dev/md1 mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. /dev/md1: Version : 00.90 Creation Time : Thu May 20 12:32:25 2010 Raid Level : raid1 Array Size : 1454645504 (1387.26 GiB 1489.56 GB) Used Dev Size : 1454645504 (1387.26 GiB 1489.56 GB) Raid Devices : 3 Total Devices : 3 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Tue Nov 12 21:30:39 2013 State : clean, degraded Active Devices : 1 Working Devices : 3 Failed Devices : 0 Spare Devices : 2 UUID : 10d7d9be:a8a50b8e:788182fa:2238f1e4 Events : 0.8717546 Number Major Minor RaidDevice State 0 0 0 0 removed 1 0 0 1 removed 2 8 34 2 active sync /dev/sdc2 3 8 18 - spare /dev/sdb2 4 8 2 - spare /dev/sda2 How do I get rid of these devices and add the new partitions as active RAID devices? Update I seem to have gotten rid of them. My RAID is resyncing, but the two drives are still marked as spares and are number 3 and 4, which looks wrong. I'll have to wait for the resync to finish. All I did was to fix the metadata error by editing my mdadm.conf and rebooting. I tried rebooting before, but this time it worked for whatever reason. Number Major Minor RaidDevice State 3 8 2 0 spare rebuilding /dev/sda2 4 8 18 1 spare rebuilding /dev/sdb2 2 8 34 2 active sync /dev/sdc2