给虚拟机加四块硬盘

/dev/sab,/dev/sdc,/dev/sdd,/dev/sde

第一：对硬盘的原始操作（四块硬盘的操作相同）

[root@Redhat ~]# fdisk /dev/sd[b,c,d,e]    //给硬盘分区
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-261, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-261, default 261):
Using default value 261
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): fd    //定格硬盘的类型为raid
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): wq

二：组建RAID5

[root@Redhat ~]#  mdadm --create /dev/md0 --level=5 --raid-device=3 -c 128 /dev/sdb1 /dev/sdc1 /dev/sdd1   //组建有三块硬盘组成的RAID5

三：创建LVM

[root@Redhat ~]# pvcreate /dev/md0   //创建PE
[root@Redhat ~]# vgcreate vg0 /dev/md0   //创建VG
[root@Redhat ~]# lvcreate -l1023 -n ethnicity vg0  //创建LV
[root@Redhat ~]# mkfs.ext3 /dev/md0    //格式化
[root@Redhat ~]# mkdir /data
[root@Redhat ~]# mount /dev/vg0/ethnicity /data/
[root@Redhat ~]# df -H
Filesystem             Size   Used  Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                        20G   6.0G    13G  32% /
/dev/sda1              104M    21M    78M  21% /boot
tmpfs                  111M      0   111M   0% /dev/shm
none                   111M   107k   111M   1% /var/lib/xenstored
/dev/mapper/vg0-ethnicity
                       4.3G    76M   4.0G   2% /data

四：LVM扩容

[root@Redhat ~]# umount /data/
[root@Redhat ~]# mdadm /dev/md0 -a /dev/sde1    //给RAID加一块硬盘
[root@Redhat ~]# mdadm --grow /dev/md0 --raid-devices=4   //设定硬盘的数量
[root@Redhat ~]# pvresize /dev/md0
[root@Redhat ~]# lvresize -l +512 /dev/vg0/ethnicity  //根据所加硬盘大小来扩容
[root@Redhat ~]# resize2fs /dev/vg0/ethnicity
resize2fs 1.39 (29-May-2006)
Please run 'e2fsck -f /dev/vg0/ethnicity' first.
[root@Redhat ~]# e2fsck -f /dev/vg0/ethnicity
[root@Redhat ~]# resize2fs /dev/vg0/ethnicity
[root@Redhat ~]# mount /dev/vg0/ethnicity /data/
[root@Redhat ~]# df -H
Filesystem             Size   Used  Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                        20G   6.0G    13G  32% /
/dev/sda1              104M    21M    78M  21% /boot
tmpfs                  111M      0   111M   0% /dev/shm
none                   111M   107k   111M   1% /var/lib/xenstored
/dev/mapper/vg0-ethnicity
                       6.4G    76M   6.1G   2% /data

这样这个小实例就成功了

以下是几个操作的笔记

1、 导出硬盘的分区状态

sfdisk -d /dev/sdb >disk.out

2、 把分区状态导入到另外的硬盘

   sfdisk /dev/sde <disk.out

3、 查看mdadm状态

cat /proc/mdstat
mdadm --detail /dev/md0

4、 LVM删除

umount /data
lvremove /dev/vg0/ethnicity
vgremove vgo
pvremove /dev/md0

5、RAID删除

mdadm /dev/md0 –fail /dev/sd[b,c,d,e]1 –remove /dev/sdb[b,c,d,e]1

6、停止RAID

     mdadm –stop /dev/md0

7、清空磁盘（分区）超级块中的RAID信息

     mdadm  --misc –zero-superblock /dev/sd[b,c,d,e]1