两块30G硬盘做RAID1

做这个实验我们需要新添加两块30G的硬盘
[root@ZZSRV1 ~]# uname -a

Linux ZZSRV1.localdomain 3.10.0-123.el7.x86_64 #1 SMP Mon Jun 30 12:09:22 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

我们可以不用重启就能显示出磁盘
[root@ZZSRV1 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@ZZSRV1 ~]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@ZZSRV1 ~]# echo "- - -" > /sys/class/scsi_host/host2/scan
查看磁盘
[root@ZZSRV1 ~]# fdisk -l

Disk /dev/sda: 42.9 GB, 42949672960 bytes, 83886080 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
Disk label type: dos
Disk identifier: 0x0003747c

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 83886079 41430016 8e Linux LVM

Disk /dev/sdb: 32.2 GB, 32212254720 bytes, 62914560 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

Disk /dev/sdc: 32.2 GB, 32212254720 bytes, 62914560 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

安装mdadm
[root@ZZSRV1 ~]# mount /dev/cdrom /mnt/cdrom/
[root@ZZSRV1 ~]# cd /mnt/cdrom/Packages/
[root@ZZSRV1 Packages]# ls mdadm*
mdadm-3.2.6-31.el7.x86_64.rpm

[root@ZZSRV1 Packages]# rpm -ivh mdadm-3.2.6-31.el7.x86_64.rpm
warning: mdadm-3.2.6-31.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
Preparing... ################################# [100%]
package mdadm-3.2.6-31.el7.x86_64 is already installed

给磁盘分区
[root@ZZSRV1 Packages]# fdisk /dev/sdb
[root@ZZSRV1 Packages]# fdisk /dev/sdc

创建RAID1卷
[root@ZZSRV1 ~]# mdadm -Cv /dev/md0 -l1 -n2 /dev/sdc1 /dev/sdb1
mdadm: /dev/sdc1 appears to contain an ext2fs file system
size=31456256K mtime=Thu Jan 1 08:00:00 1970
mdadm: Note: this array has metadata at the start and
may not be suitable as a boot device. If you plan to
store '/boot' on this device please ensure that
your boot-loader understands md/v1.x metadata, or use
--metadata=0.90
mdadm: /dev/sdb1 appears to contain an ext2fs file system
size=31456256K mtime=Thu Jan 1 08:00:00 1970
mdadm: size set to 31439744K
Continue creating array? (y/n) y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

[root@ZZSRV1 ~]# cd /
[root@ZZSRV1 /]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[1] sdc1[0]
31439744 blocks super 1.2 [2/2] [UU]
[========>............] resync = 41.6% (13101184/31439744) finish=1.5min speed=199772K/sec

unused devices: <none>

格式化RAID卷
[root@ZZSRV1 Packages]# mkfs.ext4 /dev/md0
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5238496 blocks
261924 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

[root@ZZSRV1 Packages]# mkdir /data
[root@ZZSRV1 Packages]# mount /dev/md0 /data
[root@ZZSRV1 Packages]# ll /data/
total 16
drwx------ 2 root root 16384 Aug 15 00:31 lost+found
[root@ZZSRV1 Packages]# mdadm -Ds
ARRAY /dev/md0 metadata=1.2 name=ZZSRV1.localdomain:0 UUID=c2fe6a35:461511e9:7e9bf672:9baeb95c
[root@ZZSRV1 Packages]# mdadm -Ds >> /etc/mdadm.conf

[root@ZZSRV1 Packages]# vi /etc/fstab
在最后添加
/dev/md0 /data ext4 defaults 0 0

[root@ZZSRV1 Packages]# mdadm -Ds
ARRAY /dev/md0 metadata=1.2 name=ZZSRV1.localdomain:0 UUID=c2fe6a35:461511e9:7e9bf672:9baeb95c
[root@ZZSRV1 Packages]# mdadm -Ds >> /etc/mdadm.conf

[root@ZZSRV1 Packages]# reboot
[root@ZZSRV1 ~]# mount
/dev/mapper/VolGroup-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/md0 on /data type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

[root@ZZSRV1 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[0] sdc1[1]
31438720 blocks super 1.2 [2/2] [UU]

unused devices: <none>

我们可以模拟故障
将一块30G的硬盘删除
查看日志会出现 需要等一会

sd 2:0:1:0: [sdb] Unhandled error code
sd 2:0:1:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
sd 2:0:1:0: [sdb] CDB: Write(10): 2a 00 00 00 00 47 00 00 01 00
md: super_written gets error=-5, uptodate=0
md/raid1:md0: Disk failure on sdb1, disabling device.
md/raid1:md0: Operation continuing on 1 devices.
RAID1 conf printout:
--- wd:1 rd:2
disk 0, wo:1, o:0, dev:sdb1
disk 1, wo:0, o:1, dev:sdc1
RAID1 conf printout:
--- wd:1 rd:2
disk 1, wo:0, o:1, dev:sdc1
sd 2:0:1:0: [sdb] Unhandled error code
sd 2:0:1:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
sd 2:0:1:0: [sdb] CDB: Write(10): 2a 00 00 00 00 47 00 00 01 00
md: super_written gets error=-5, uptodate=0
md/raid1:md0: Disk failure on sdb1, disabling device.
md/raid1:md0: Operation continuing on 1 devices.

[root@ZZSRV1 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[0](F) sdc1[1]
31438720 blocks super 1.2 [2/1] [_U]

unused devices: <none>

有了故障我们就需要重建RAID1
模拟恢复，添加一块新的30G硬盘

[root@ZZSRV1 ~]# fdisk -l /dev/sdb

Disk /dev/sdb: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x9b6ff607

Device Boot Start End Blocks Id System
/dev/sdb1 2048 62914559 31456256 83 Linux

在线加入新组成单元

[root@ZZSRV1 ~]# mdadm /dev/md0 -a /dev/sdb1
mdadm: added /dev/sdb1
[root@ZZSRV1 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[2] sdc1[1]
31438720 blocks super 1.2 [2/1] [_U]
[=>...................] recovery = 7.0% (2201920/31438720) finish=2.4min speed=200174K/sec

unused devices: <none>

在日志中我们可以看到重建过程
md: bind<sdb1>
md: recovery of RAID array md0
md: minimum _guaranteed_ speed: 1000 KB/sec/disk.
md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery.
md: using 128k window, over a total of 31438720k.
md: md0: recovery done.