# mdadm –help
mdadm is used for building, managing, and monitoring
Linux md devices (aka RAID arrays)
Usage: mdadm –create device options…
Create a new array from unused devices.
mdadm –assemble device options…
Assemble a previously created array.
mdadm –build device options…
Create or assemble an array without metadata.
mdadm –manage device options…
make changes to an existing array.
mdadm –misc options… devices
report on or modify various md related devices.
mdadm –grow options device
resize/reshape an active array
mdadm –incremental device
add/remove a device to/from an array as appropriate
mdadm –monitor options…
Monitor one or more array for significant changes.[@more@]列出常用指令
# mdadm –create –help
Usage: mdadm –create device -chunk=X –level=Y –raid-devices=Z devices
–level= -l : raid level: 0,1,4,5,6,10,linear,multipath and synonyms
–raid-devices= -n : number of active devices in array
Example：
# mdadm –create /dev/md0 –level=stripe –raid-devices=4 /dev/sd[b-e]1
# mdadm –create /dev/md0 –level=5 –raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
# mdadm –create /dev/md0 –level=6 –raid-devices=4 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
# mdadm -E /dev/sd[b-e]
# mdadm –examine /dev/sd[b-e]
# mdadm –examine /dev/sdb /dev/sdc /dev/sdd /dev/sde
/dev/sdb:
MBR Magic : aa55
Partition[0] : 41940992 sectors at 2048 (type fd)
/dev/sdc:
MBR Magic : aa55
Partition[0] : 41940992 sectors at 2048 (type fd)
/dev/sdd:
MBR Magic : aa55
Partition[0] : 41940992 sectors at 2048 (type fd)
/dev/sde:
MBR Magic : aa55
Partition[0] : 41940992 sectors at 2048 (type fd)
顯示 RAID 資訊
# mdadm –detail /dev/md0
# 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
# mdadm –detail –scan –verbose
ARRAY /dev/md/0 level=raid6 num-devices=4 metadata=1.2 name=debian:0 UUID=8f039d29:9179c09a:17a76417:e54c9dfa
devices=/dev/sdb1,/dev/sdc1,/dev/sdd1,/dev/sde1
停止 RAID
# mdadm –manage –stop /dev/md0
啟動 RAID
# mdadm –assemble –run /dev/md0
# mdadm -A –run /dev/md0
模擬磁碟故障
# mdadm –manage /dev/md0 –fail /dev/sdd1
# mdadm –manage /dev/md0 –set-faulty /dev/sdd1
加入磁碟到 RAID 中
# mdadm –manage /dev/md0 –add /dev/sdf1
從 RAID 中移除磁碟
# mdadm –manage /dev/md0 –remove /dev/sdd1