I recently had to reinstall RL9.2 from scratch on a server with 4 identical drives. During the install, I opted for manual partitioning, selected 3 of the 4 drives, and asked that /home be configured as a RAID 5 with the intention of adding the 4th drive as a spare later.
When I tried to use the command
mdadm --add /dev/md125 /dev/sdi2
mdadm complains “Cannot open /dev/sdi2: Device or resource busy”.
cat /proc/mdstat reports:
Personalities : [raid6] [raid5] [raid4]
md124 : active (auto-read-only) raid5 sdh4[3] sdg4[1] sdf6[0]
6988820480 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
bitmap: 0/27 pages [0KB], 65536KB chunk
md125 : active raid4 sdh2[3] sdg2[1] sdf4[0]
700628992 blocks super 1.2 level 4, 512k chunk, algorithm 0 [3/3] [UUU]
bitmap: 2/3 pages [8KB], 65536KB chunk
md126 : active (auto-read-only) raid5 sdh6[3] sdg6[1] sdf8[0]
48896000 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
bitmap: 0/1 pages [0KB], 65536KB chunk
md127 : inactive sdi2 [3] (S)
3875872768 blocks super 1.2
Does the (S) on md127 mean that RL automatically created it as a spare?
lsblk reports:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 1 114.6G 0 disk
└─sda1 8:1 1 114.6G 0 part
sdb 8:16 1 0B 0 disk
sdc 8:32 1 0B 0 disk
sdd 8:48 1 0B 0 disk
sde 8:64 1 0B 0 disk
sdf 8:80 0 3.6T 0 disk
├─sdf1 8:81 0 1M 0 part
├─sdf2 8:82 0 1G 0 part /boot
├─sdf3 8:83 0 28.6G 0 part
│ ├─rl_server200-root 253:0 0 70G 0 lvm /
│ └─rl_server200-swap 253:2 0 15.7G 0 lvm [SWAP]
├─sdf4 8:84 0 334.2G 0 part
│ └─md125 9:125 0 668.2G 0 raid4 /home
├─sdf5 8:85 0 1G 0 part
├─sdf6 8:86 0 3.3T 0 part
│ └─md124 9:124 0 6.5T 0 raid5
├─sdf7 8:87 0 5.2G 0 part
│ └─rl_server2-swap 253:1 0 15.7G 0 lvm
└─sdf8 8:88 0 23.3G 0 part
└─md126 9:126 0 46.6G 0 raid5
sdg 8:96 0 3.6T 0 disk
├─sdg1 8:97 0 28.6G 0 part
│ └─rl_server200-root 253:0 0 70G 0 lvm /
├─sdg2 8:98 0 334.2G 0 part
│ └─md125 9:125 0 668.2G 0 raid4 /home
├─sdg4 8:100 0 3.3T 0 part
│ └─md124 9:124 0 6.5T 0 raid5
├─sdg5 8:101 0 5.2G 0 part
│ └─rl_server2-swap 253:1 0 15.7G 0 lvm
└─sdg6 8:102 0 23.3G 0 part
└─md126 9:126 0 46.6G 0 raid5
sdh 8:112 0 3.6T 0 disk
├─sdh1 8:113 0 28.6G 0 part
│ └─rl_server200-root 253:0 0 70G 0 lvm /
├─sdh2 8:114 0 334.2G 0 part
│ └─md125 9:125 0 668.2G 0 raid4 /home
├─sdh4 8:116 0 3.3T 0 part
│ └─md124 9:124 0 6.5T 0 raid5
├─sdh5 8:117 0 5.2G 0 part
│ └─rl_server2-swap 253:1 0 15.7G 0 lvm
└─sdh6 8:118 0 23.3G 0 part
└─md126 9:126 0 46.6G 0 raid5
sdi 8:128 0 3.6T 0 disk
├─sdi1 8:129 0 28.6G 0 part
└─sdi2 8:130 0 3.6T 0 part
└─md127 9:127 0 0B 0 md
sr0 11:0 1 1024M 0 rom
==================
How do I recover from this and add sdi as a RAID spare?
P.S. I don’t know what all the funny characters in lsblk are about.
df reports:
Filesystem 1K-blocks Used Available Use% Mounted on
devtmpfs 4096 0 4096 0% /dev
tmpfs 16284808 0 16284808 0% /dev/shm
tmpfs 6513924 11284 6502640 1% /run
/dev/mapper/rl_server200-root 73364480 5826484 67537996 8% /
/dev/sdf2 1038336 472292 566044 46% /boot
/dev/md125 700286888 43740960 656545928 7% /home
tmpfs 3256960 112 3256848 1% /run/user/1000
//192.1.1.12/rocky-dd 17578326008 13072738248 4505587760 75% /mnt/rocky-dd
===================
df /home tells me that /home is mounted on md125. I am also confused as to why mdstat also tells me I have md124, md126, and md127 present. I didnt intend to create any of those.