案例二：使用磁盘分区和磁盘阵列(Raid5)创建逻辑卷
要求：使用2块磁盘分区进行逻辑卷的创建，3块磁盘做Raid5后创建成逻辑卷
1.磁盘分区（/dev/sdc不做分区，使用整块磁盘。/dev/sdd,/dev/sde,/dev/sdf分区方法相同，这里不再赘述）
[root@lyt ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
The number of cylinders for this disk is set to 2610.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): p
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-2610, default 2610): +200M
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System、
/dev/sdb1 1 25 200781 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@lyt ~]#
2.创建Raid5（使用/dev/sdd1,/dev/sde1,/dev/sdf1）
[root@lyt ~]# mdadm -Cv /dev/md0 -l 5 -n 3 /dev/sdd1 /dev/sde1 /dev/sdf1 #C表示创建，v表示显示详细信息，md0是设备。-l表示创建raid的级别，-n表示成员数量
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 64K
mdadm: size set to 200704K
mdadm: array /dev/md0 started.
[root@lyt ~]# mdadm -Cv /dev/md1 -l 5 -n 3 /dev/sdd2 /dev/sde2 /dev/sdf2
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 64K
mdadm: size set to 200704K
mdadm: array /dev/md1 started.。
[root@lyt ~]# cat /proc/mdstat #查看状态
Personalities : [raid6] [raid5] [raid4]
md1 : active raid5 sdf2[2] sde2[1] sdd2[0]
401408 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
md0 : active raid5 sdf1[2] sde1[1] sdd1[0]
401408 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
unused devices: <none>
[root@lyt ~]# mdadm --detail /dev/md0 #查看md0的详细信息
/dev/md0:
Version : 0.90
Creation Time : Mon Dec 24 21:09:25 2012
Raid Level : raid5
Array Size : 401408 (392.07 MiB 411.04 MB)
Used Dev Size : 200704 (196.03 MiB 205.52 MB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Mon Dec 24 21:12:38 2012
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : b5680dee:d452c142:037e51af:5c72eea9
Events : 0.2
Number Major Minor RaidDevice State
0 8 49 0 active sync /dev/sdd1
1 8 65 1 active sync /dev/sde1
2 8 81 2 active sync /dev/sdf1
[root@lyt ~]# mdadm --detail /dev/md1 #查看md1的详细信息
/dev/md1:
Version : 0.90
Creation Time : Mon Dec 24 21:10:02 2012
Raid Level : raid5
Array Size : 401408 (392.07 MiB 411.04 MB)
Used Dev Size : 200704 (196.03 MiB 205.52 MB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Mon Dec 24 21:12:40 2012
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : 931454bb:a68d6779:fa0087fb:b8609ca6
Events : 0.2
Number Major Minor RaidDevice State
0 8 50 0 active sync /dev/sdd2
1 8 66 1 active sync /dev/sde2
2 8 82 2 active sync /dev/sdf2
[root@lyt ~]#
3.创建物理卷
[root@lyt ~]# pvcreate /dev/sdb1 #分区
Physical volume "/dev/sdb1" successfully created
[root@lyt ~]# pvcreate /dev/sdc #整块磁盘
Physical volume "/dev/sdc" successfully created
[root@lyt ~]# pvcreate /dev/md0 #Raid5创建成物理卷
Physical volume "/dev/md0" successfully created
[root@lyt ~]# pvcreate /dev/md1 #Raid5创建成物理卷
Physical volume "/dev/md1" successfully created
4.创建卷组
[root@lyt ~]# vgcreate testvg /dev/sdb1 /dev/sdc /dev/md0 /dev/md1
/dev/cdrom: open failed: Read-only file system
Attempt to close device '/dev/cdrom' which is not open.
Volume group "testvg" successfully created
5.创建逻辑卷
[root@lyt ~]# lvcreate -L 1000M -n testlv testvg #-L表示大小，-n表示名字
Logical volume "testlv" created
6.格式化逻辑卷
[root@lyt ~]# mkfs -t ext3 /dev/testvg/testlv #格式化
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
128000 inodes, 256000 blocks
12800 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=264241152
8 block groups
32768 blocks per group, 32768 fragments per group
16000 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 25 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@lyt ~]#
7.挂载
[root@lyt ~]# mkdir /testlv
[root@lyt ~]# mount /dev/testvg/testlv /testlv/
[root@lyt ~]# ll /testlv/
total 16
drwx------ 2 root root 16384 Dec 24 21:24 lost+found
[root@lyt testlv]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
18G 2.6G 15G 15% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 179M 0 179M 0% /dev/shm
/dev/mapper/testvg-testlv
985M 18M 918M 2% /testlv
