针对mdadm的RAID1失效测试
Posted felix-zp
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了针对mdadm的RAID1失效测试相关的知识，希望对你有一定的参考价值。
背景
对软RAID（mdadm）方式进行各个场景失效测试。
一、初始信息
内核版本：
[email protected]:~# uname -a
Linux omv30 4.18.0-0.bpo.1-amd64 #1 SMP Debian 4.18.6-1~bpo9+1 (2018-09-13) x86_64 GNU/Linux使用omv创建RAID1之后，查询sdb的信息，此时sdb对应的是8ac693c5的UUID，device号为1：
[email protected]:~# mdadm --query /dev/sdb
/dev/sdb: is not an md array
/dev/sdb: device 1 in 2 device undetected raid1 /dev/md0. Use mdadm --examine for more detail.[email protected]:~# mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Name : omv30:raid1 (local to host omv30)
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 2095104 (1023.00 MiB 1072.69 MB)
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1960 sectors, after=0 sectors
State : clean
Device UUID : 64a58fb5:c7e76b1a:29453878:8ac693c5
Update Time : Mon Oct 1 13:20:56 2018
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : 2e1fb65b - correct
Events : 21
Device Role : Active device 1
Array State : AA (‘A‘ == active, ‘.‘ == missing, ‘R‘ == replacing)[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 19:46:42 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 25
Number Major Minor RaidDevice State
0 8 32 0 active sync /dev/sdc
1 8 16 1 active sync /dev/sdb配置文件信息：
[email protected]:~# cat /etc/mdadm/mdadm.conf
# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#
# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
# Note, if no DEVICE line is present, then "DEVICE partitions" is assumed.
# To avoid the auto-assembly of RAID devices a pattern that CAN‘T match is
# used if no RAID devices are configured.
DEVICE partitions
# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes
# automatically tag new arrays as belonging to the local system
HOMEHOST <system>
# definitions of existing MD arrays
ARRAY /dev/md0 metadata=1.2 name=omv30:raid1 UUID=921a8946:b273e00e:3fa4b99d:040a4437二、盘符错乱测试
1、盘符交换测试
在VirtualBox的存储-SATA下，分别选中两块硬盘，在右边的属性将SATA端口调换位置，即可交换盘符。
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 19:52:46 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 29
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc可以看到盘符已经换了。
[email protected]:~# mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Name : omv30:raid1 (local to host omv30)
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 2095104 (1023.00 MiB 1072.69 MB)
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1960 sectors, after=0 sectors
State : clean
Device UUID : 6e545465:3dcf10df:1d5bb938:fe840307
Update Time : Mon Oct 1 19:52:46 2018
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : a47a7d1f - correct
Events : 29
Device Role : Active device 0
Array State : AA (‘A‘ == active, ‘.‘ == missing, ‘R‘ == replacing)[email protected]:~# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active (auto-read-only) raid1 sdb[0] sdc[1]
1047552 blocks super 1.2 [2/2] [UU]
unused devices: <none>
[email protected]:~# fdisk -l
...（省略）
Disk /dev/md0: 1023 MiB, 1072693248 bytes, 2095104 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytesmount后访问正常。
2、更换硬盘位置测试
关机，新增一块硬盘，占用原来sdc的位置，启动：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 19:52:46 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 29
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 48 1 active sync /dev/sdd[email protected]:~# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active (auto-read-only) raid1 sdb[0] sdd[1]
1047552 blocks super 1.2 [2/2] [UU]
unused devices: <none>原来的sdc变成了sdc，raid1还完好保存，不受影响。
3、移除硬盘测试
关机，然后移除一块硬盘，启动：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Raid Level : raid0
Total Devices : 1
Persistence : Superblock is persistent
State : inactive
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 29
Number Major Minor RaidDevice
- 8 16 - /dev/sdb[email protected]:~# mdadm --query /dev/sdb
/dev/sdb: is not an md array
/dev/sdb: device 0 in 2 device undetected raid1 /dev/md0. Use mdadm --examine for more detail.[email protected]:~# mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Name : omv30:raid1 (local to host omv30)
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 2095104 (1023.00 MiB 1072.69 MB)
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1960 sectors, after=0 sectors
State : clean
Device UUID : 6e545465:3dcf10df:1d5bb938:fe840307
Update Time : Mon Oct 1 19:52:46 2018
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : a47a7d1f - correct
Events : 29
Device Role : Active device 0
Array State : AA (‘A‘ == active, ‘.‘ == missing, ‘R‘ == replacing)[email protected]:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdb[0](S)
1047552 blocks super 1.2
unused devices: <none>[email protected]:~# fdisk -l
Disk /dev/sda: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x8c9b0fb9
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 12582911 12580864 6G 83 Linux
/dev/sda2 12584958 16775167 4190210 2G 5 Extended
/dev/sda5 12584960 16775167 4190208 2G 82 Linux swap / Solaris
Disk /dev/sdb: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytesraid1变成了inactive，但raid信息本身是保存在磁盘中，不会丢失。
4、结论
- mdadm不是根据盘符/dev/sdx来记录RAID信息的，盘符无论怎么变换，RAID信息不错乱。
- mdadm是使用Device UUID来区分硬盘的。与RAID硬盘盒不一样，硬盘盒是记录硬盘槽位号的。
- 所以mdadm每个硬盘可以使用任意硬盘盒，不用记录位置。
三、RAID降级恢复测试
场景：正常运行的RAID1，突然一块盘失效，进行重建恢复。
方法：可以用模拟fail的方式，也可以用VirtualBox热插拔硬盘的功能。
1、模拟fail的方式
初始信息如下：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 20:29:44 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 31
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 48 1 active sync /dev/sdd(1)手工fail掉sdd：
[email protected]:~# mdadm /dev/md0 --fail /dev/sdd
mdadm: set /dev/sdd faulty in /dev/md0[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 20:29:59 2018
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 1
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 33
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
- 0 0 1 removed
1 8 48 - faulty /dev/sdd如果未移除，要先移除损坏的硬盘：
[email protected]:~# mdadm /dev/md0 -r /dev/sdd
mdadm: hot remove failed for /dev/sdd: No such device or address(2)增加新盘：
[email protected]:~# mdadm /dev/md0 --add /dev/sdc （新加的盘是2G的，经实测不影响RAID1重建）
mdadm: added /dev/sdc
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 20:36:22 2018
State : clean, degraded, recovering
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1
Rebuild Status : 76% complete
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 48
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
2 8 32 1 spare rebuilding /dev/sdc可以看到正在重建。
过一会儿再执行：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 20:36:24 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 53
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
2 8 32 1 active sync /dev/sdc[email protected]:~# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc[2] sdb[0]
1047552 blocks super 1.2 [2/2] [UU]
unused devices: <none>已经重建成功。
2、热插拔硬盘测试
在VirtualBox的存储中，勾选sdb的热插拔，然后启动。
系统在运行时，到VirtualBox的存储中移除sdb硬盘，然后查看状态：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent
Update Time : Mon Oct 1 21:13:45 2018
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 56
Number Major Minor RaidDevice State
- 0 0 0 removed
2 8 32 1 active sync /dev/sdc查看系统日志，发现有硬盘离线，并且RAID1降级（有日志跟踪是软RAID的一个优势）：
[email protected]:/var/log# dmesg | tail -20
[ 340.551533] md: recovery of RAID array md0
[ 345.881625] md: md0: recovery done.
[ 657.932091] EXT4-fs (md0): mounted filesystem with ordered data mode. Opts: (null)
[ 2571.324851] ata2: SATA link down (SStatus 0 SControl 300)
[ 2576.667851] ata2: SATA link down (SStatus 0 SControl 300)
[ 2582.044796] ata2: SATA link down (SStatus 0 SControl 300)
[ 2582.044864] ata2.00: disabled
[ 2582.045573] ata2.00: detaching (SCSI 3:0:0:0)
[ 2582.058467] sd 3:0:0:0: [sdb] Synchronizing SCSI cache
[ 2582.058528] sd 3:0:0:0: [sdb] Synchronize Cache(10) failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[ 2582.058536] sd 3:0:0:0: [sdb] Stopping disk
[ 2582.058552] sd 3:0:0:0: [sdb] Start/Stop Unit failed: Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[ 2586.709149] md/raid1:md0: Disk failure on sdb, disabling device.
md/raid1:md0: Operation continuing on 1 devices.加入新硬盘。新加的硬盘不能比现有的小，可以比现在的大。
[email protected]:~# mdadm /dev/md0 --add /dev/sdc开始重建：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 21:38:36 2018
State : clean, degraded, recovering
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1
Rebuild Status : 56% complete
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 69
Number Major Minor RaidDevice State
3 8 32 0 spare rebuilding /dev/sdc
2 8 16 1 active sync /dev/sdb[email protected]:~# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc[3] sdb[2]
1047552 blocks super 1.2 [2/1] [_U]
[===================>.] recovery = 95.0% (996288/1047552) finish=0.0min speed=249072K/sec
unused devices: <none>重建完成：
[email protected]:~# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 21:38:39 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Name : omv30:raid1 (local to host omv30)
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 78
Number Major Minor RaidDevice State
3 8 32 0 active sync /dev/sdc
2 8 16 1 active sync /dev/sdb[email protected]:~# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc[3] sdb[2]
1047552 blocks super 1.2 [2/2] [UU]
unused devices: <none>四、重装系统恢复RAID1测试
1、RAID1两块硬盘正常
将两块硬盘挂到一个新装的ubuntu中，启动。
[email protected]:/home/op# fdisk -l
...（省略）
Disk /dev/md127：1023 MiB，1072693248 字节，2095104 个扇区
单元：扇区 / 1 * 512 = 512 字节
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节[email protected]:/home/op# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md127 : active raid1 sdd[1] sdc[0]
1047552 blocks super 1.2 [2/2] [UU]
unused devices: <none>可以看到，自动识别出来/dev/md127。
[email protected]:/mnt/md# mdadm -D /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Mon Oct 1 19:31:08 2018
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Consistency Policy : resync
Name : omv30:raid1
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 25
Number Major Minor RaidDevice State
0 8 32 0 active sync /dev/sdc
1 8 48 1 active sync /dev/sdd系统自动识别并恢复了RAID1，不用执行mdadm --assemble --scan。
查看/etc/mdadm/mdadm.conf，也是自动加入了md信息。
mount后访问正常。
至于如何将md127修改成md0，详见下一节。
2、RAID1损坏了一块硬盘
只有一块硬盘可用，需要在新系统上重建RAID1。
[email protected]:/home/op# fdisk -l
（未发现新的md设备，略去详细输出）[email protected]:/home/op# mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Name : omv30:raid1
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 4192256 (2047.00 MiB 2146.44 MB)
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 2095104 (1023.00 MiB 1072.69 MB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1960 sectors, after=2097152 sectors
State : clean
Device UUID : 6e2fc709:35a8f6fb:d4c0e242:6905437d
Update Time : Mon Oct 1 21:40:25 2018
Bad Block Log : 512 entries available at offset 72 sectors
Checksum : e65b30a8 - correct
Events : 78
Device Role : Active device 1
Array State : AA (‘A‘ == active, ‘.‘ == missing, ‘R‘ == replacing)[email protected]:/home/op# cat /proc/mdstat
Personalities :
unused devices: <none>说明新挂载的盘RAID1信息犹在，只需要重新识别：
[email protected]:/home/op# mdadm --assemble --scan
mdadm: /dev/md/raid1 has been started with 1 drive (out of 2).[email protected]:/home/op# fdisk -l
...（省略）
Disk /dev/md127：1023 MiB，1072693248 字节，2095104 个扇区
单元：扇区 / 1 * 512 = 512 字节
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节[email protected]:/home/op# mdadm -D /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Sun Sep 30 22:31:39 2018
Raid Level : raid1
Array Size : 1047552 (1023.00 MiB 1072.69 MB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent
Update Time : Mon Oct 1 21:40:25 2018
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Consistency Policy : resync
Name : omv30:raid1
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 78
Number Major Minor RaidDevice State
- 0 0 0 removed
2 8 16 1 active sync /dev/sdb如果这个时间重启系统，会发现fdisk -l中没有md127了。并且mdadm -D发现RAID1处于inactive。
[email protected]:/home/op# mdadm -D /dev/md127
/dev/md127:
Version : 1.2
Raid Level : raid0
Total Devices : 1
Persistence : Superblock is persistent
State : inactive
Working Devices : 1
Name : omv30:raid1
UUID : 921a8946:b273e00e:3fa4b99d:040a4437
Events : 78
Number Major Minor RaidDevice
- 8 16 - /dev/sdb这时需要先mdadm -S /dev/md127删除旧的md127，
再重新mdadm --assemble --scan。
再add硬盘，完成重建即可。
[email protected]:~# mdadm /dev/md0 --add /dev/sdc这时再重启也不会有影响，唯一的变化就是在之前主机是md0，现在变成了md127了。
解决方法：
修改/etc/mdadm/mdadm.conf，
把第二列：/dev/md/raid1
修改成：/dev/md0
再执行：
update-initramfs -u重启，搞定。
五、常用命令
查看状态
mdadm -D /dev/md0
cat /proc/mdstat
mdadm --examine /dev/sdb删除md
mdadm -S /dev/md0激活md
mdadm -A /dev/md0在新OS上重新导入raid
mdadm --assemble --scan重建
mdadm /dev/md0 --add /dev/sdc以上是关于针对mdadm的RAID1失效测试的主要内容，如果未能解决你的问题，请参考以下文章