iscsi+mdadm 建立镜像

1，硬盘环境

[root@rac1 /]# fdisk -l...Disk /dev/sdb: 536 MB, 536870912 bytes64 heads, 32 sectors/track, 512 cylindersUnits = cylinders of 2048 * 512 = 1048576 bytes

Device Boot Start End Blocks Id System

[root@rac2 ~]# fdisk -l

...Disk /dev/sdb: 536 MB, 536870912 bytes64 heads, 32 sectors/track, 512 cylindersUnits = cylinders of 2048 * 512 = 1048576 bytes

Device Boot Start End Blocks Id System

[root@rac2 ~]# 2，在rac2上配置 iscsi-target在rac2上设置/etc/ietd.conf配置文件为：Target iqn.2001-04.com.example:storage.disk2.sys1.idiskLun 4 Path=/dev/sdb,Type=fileioAlias sdb

3，启动iscsi-target服务：

[root@rac2 ~]# /etc/init.d/iscsi-target startStarting iSCSI target service: [ OK ]

4，在rac1上配置/etc/iscsi.conf

修改下面3项：DiscoveryAddress=This needs to be set to the Group IP Address of your UIT Array.

SendAsyncText=yes

For the initiator to receive Vendor Specific async events from the target.

Continuous=yes

To globally specify that all discovery sessions be kept open.

5，启动服务

[root@rac1 /]# /etc/init.d/iscsi startChecking iscsi config: [ OK ]Loading iscsi driver: [ OK ]mknod: `/dev/iscsictl': File existsStarting iscsid: [ OK ][root@rac1 /]#

6，此时fdisk结果为：

[root@rac1 /]# fdisk -l

Disk /dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/dev/sda1 * 1 892 7164958+ 83 Linux/dev/sda2 893 1274 3068415 82 Linux swap/dev/sda3 1275 2610 10731420 83 Linux

Disk /dev/sdb: 536 MB, 536870912 bytes

64 heads, 32 sectors/track, 512 cylindersUnits = cylinders of 2048 * 512 = 1048576 bytes

Device Boot Start End Blocks Id System

Disk /dev/sdc: 536 MB, 536870912 bytes

17 heads, 61 sectors/track, 1011 cylindersUnits = cylinders of 1037 * 512 = 530944 bytes

Device Boot Start End Blocks Id System

[root@rac1 /]#

rac1增加一个盘sdc，用/dev/sdb,/dev/sdc做镜像。

7，使用mdadm创建RAID1[root@rac1 /]# mdadm --create --verbose /dev/md0 --level=raid1 --raid-devices=2 /dev/sdb /dev/sdcmdadm: size set to 524224Kmdadm: array /dev/md0 started.[root@rac1 /]#

每个mdadm的选项都有一个所写的形式，例如，上面的命令可以缩写为：

mdadm -Cv /dev/md0 -l1 -n2 /dev/sdb /dev/sdc

此时fdisk显示：[root@rac1 /]# fdisk -l......Disk /dev/sdb: 536 MB, 536870912 bytes64 heads, 32 sectors/track, 512 cylindersUnits = cylinders of 2048 * 512 = 1048576 bytes

Device Boot Start End Blocks Id System

Disk /dev/md0: 536 MB, 536805376 bytes

2 heads, 4 sectors/track, 131056 cylindersUnits = cylinders of 8 * 512 = 4096 bytes

Device Boot Start End Blocks Id System

Disk /dev/sdc: 536 MB, 536870912 bytes

17 heads, 61 sectors/track, 1011 cylindersUnits = cylinders of 1037 * 512 = 530944 bytes

Device Boot Start End Blocks Id System

[root@rac1 /]#

8,查看raid信息：

使用cat /proc/mdstat命令来查看一下RAID的状态，我们也可以利用watch命令来每隔一段时间刷新/proc/mdstat的输出。使用CTRL+C可以取消。使用mdadm --detail /dev/md0(或mdadm -D /dev/md0)命令以及cat /proc/mdstat命令可以查看RAID设备的状态：

[root@rac1 /]# cat /proc/mdstat

Personalities : [raid1] [raid5] md0 : active raid1 sdc[1] sdb[0] 524224 blocks [2/2] [UU]unused devices: [root@rac1 /]# mdadm -D /dev/md0/dev/md0: Version : 00.90.01 Creation Time : Thu Oct 25 15:28:07 2007 Raid Level : raid1 Array Size : 524224 (511.94 MiB 536.81 MB) Device Size : 524224 (511.94 MiB 536.81 MB) Raid Devices : 2 Total Devices : 2Preferred Minor : 0 Persistence : Superblock is persistent

Update Time : Thu Oct 25 15:30:24 2007

State : clean Active Devices : 2Working Devices : 2 Failed Devices : 0 Spare Devices : 0

Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 1 8 32 1 active sync /dev/sdc UUID : 081c04ac:6cb9278e:35bade9d:49098be4 Events : 0.34[root@rac1 /]#

[root@rac1 /]# mdadm --detail /dev/md0

...

9,为阵列建立文件系统

[root@rac1 /]# mkfs.ext3 /dev/md0mke2fs 1.35 (28-Feb-2004)Filesystem label=OS type: LinuxBlock size=1024 (log=0)Fragment size=1024 (log=0)131072 inodes, 524224 blocks26211 blocks (5.00%) reserved for the super userFirst data block=1Maximum filesystem blocks=6763315264 block groups8192 blocks per group, 8192 fragments per group2048 inodes per groupSuperblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409

Writing inode tables: done

Creating journal (8192 blocks): doneWriting superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 22 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.[root@rac1 /]# mkdir /mnt/md0[root@rac1 /]# mount /dev/md0 /mnt/md0[root@rac1 /]# cd /mnt/md0[root@rac1 md0]# lslost+found[root@rac1 md0]# touch test[root@rac1 md0]# lslost+found test[root@rac1 md0]#

10,创建/etc/mdadm.conf配置文件一个新阵列被创建后我们最好创建一个/etc/mdadm.conf文件。没有该文件在激活阵列时我们就得指定更详细的信息，为方便，我们使用下列命令：[root@rac1 /]# mdadm --detail --scanARRAY /dev/md0 level=raid1 num-devices=2 UUID=081c04ac:6cb9278e:35bade9d:49098be4 devices=/dev/sdb,/dev/sdc[root@rac1 /]# mdadm --detail --scan > /etc/mdadm.conf[root@rac1 /]# cat /etc/mdadm.confARRAY /dev/md0 level=raid1 num-devices=2 UUID=081c04ac:6cb9278e:35bade9d:49098be4 devices=/dev/sdb,/dev/sdc[root@rac1 /]#

11，启动停止RAID使用--stop或-S命令选项可以停止运行的阵列(注意： 停止前必须先umount)：[root@rac1 /]# umount /mnt/md0[root@rac1 /]# mdadm -S /dev/md0 (或mdadm --stop /dev/md0)

重新启动可以使用：

[root@rac1 /]# mdadm -As /dev/md0mdadm: no devices found for /dev/md0

启动时报错，

新的配置文件应该这样创建：

[root@rac1 ~]# echo DEVICE /dev/sd* > /etc/mdadm.conf[root@rac1 ~]# mdadm --detail --scan >> /etc/mdadm.conf[root@rac1 ~]# cat /etc/mdadm.confDEVICE /dev/sda /dev/sda1 /dev/sda2 /dev/sda3 /dev/sdb /dev/sdcARRAY /dev/md0 level=raid1 num-devices=2 UUID=081c04ac:6cb9278e:35bade9d:49098be4 devices=/dev/sdb,/dev/sdc[root@rac1 ~]#

然后重新测试关闭启动

[root@rac1 ~]# mdadm --stop /dev/md0[root@rac1 ~]# mdadm -As /dev/md0mdadm: /dev/md0 has been started with 2 drives.[root@rac1 ~]#

当没有配置文件的时候可以用如下方式启动：[root@rac1 /]# umount /dev/md0[root@rac1 /]# mdadm -S /dev/md0[root@rac1 /]# mdadm -A /dev/md0 /dev/sdb /dev/sdcmdadm: /dev/md0 has been started with 2 drives.[root@rac1 /]#

来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/312079/viewspace-245788/，如需转载，请注明出处，否则将追究法律责任。