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磁碟管理：SoftRAID 與 LVM 綜合實做應用（上）
以 Debian Linux RAID 6 為例
1. 原本的 RAID 狀態
# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Tue Jun 28 10:25:06 2016
Raid Level : raid6
Array Size : 41908224 (39.97 GiB 42.91 GB)
Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Tue Jun 28 10:36:08 2016
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : debian:0 (local to host debian)
UUID : 8f039d29:9179c09a:17a76417:e54c9dfa
Events : 23
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 65 3 active sync /dev/sde1[@more@]2. 模擬 /dev/sdd1 故障
# mdadm –manage –fail /dev/md0 /dev/sdd1
# mdadm –manage –set-faulty /dev/md0 /dev/sdd1
mdadm: set /dev/sdd1 faulty in /dev/md0
3. 檢查目前的 RAID 狀態
# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Tue Jun 28 10:25:06 2016
Raid Level : raid6
Array Size : 41908224 (39.97 GiB 42.91 GB)
Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Tue Jun 28 11:12:01 2016
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 1
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : debian:0 (local to host debian)
UUID : 8f039d29:9179c09a:17a76417:e54c9dfa
Events : 25
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
4 0 0 4 removed
3 8 65 3 active sync /dev/sde1
2 8 49 – faulty /dev/sdd1
sdd1[2](F) 後面 F 代表故障，md0 的最後一行 [4/3]與[UU_U]表示出有一顆磁碟壞掉了
# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid6 sdb1[0] sde1[3] sdd1[2](F) sdc1[1]
41908224 blocks super 1.2 level 6, 512k chunk, algorithm 2 [4/3] [UU_U]
unused devices: <none>
4. 將故障的硬碟移出
# mdadm –manage –remove /dev/md0 /dev/sdd1
mdadm: hot removed /dev/sdd1 from /dev/md0
5. 檢視移除 /dev/sdd1 的 RAID 狀態
# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Tue Jun 28 10:25:06 2016
Raid Level : raid6
Array Size : 41908224 (39.97 GiB 42.91 GB)
Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 3
Persistence : Superblock is persistent
Update Time : Tue Jun 28 11:20:14 2016
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : debian:0 (local to host debian)
UUID : 8f039d29:9179c09a:17a76417:e54c9dfa
Events : 26
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
4 0 0 4 removed
3 8 65 3 active sync /dev/sde1
6. 將新加入的 /dev/sdf 磁碟機建立磁碟分割
# fdisk /dev/sdf
7. 將新增的 /dev/sdf1 加入到 RAID 中
# mdadm –manage –add /dev/md0 /dev/sdf1
mdadm: added /dev/sdf1
8. 再次檢視 RAID 狀態
# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Tue Jun 28 10:25:06 2016
Raid Level : raid6
Array Size : 41908224 (39.97 GiB 42.91 GB)
Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Tue Jun 28 11:29:08 2016
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Rebuild Status : 49% complete
Name : debian:0 (local to host debian)
UUID : 8f039d29:9179c09a:17a76417:e54c9dfa
Events : 39
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
4 8 81 2 spare rebuilding /dev/sdf1
3 8 65 3 active sync /dev/sde1
# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid6 sdf1[4] sdb1[0] sde1[3] sdc1[1]
41908224 blocks super 1.2 level 6, 512k chunk, algorithm 2 [4/3] [UU_U]
[=============>…….] recovery = 67.1% (14066688/20954112) finish=0.9min speed=124729K/sec
unused devices: <none>