Linux存储实验二：LVM操作
基本知识讲解请参考鸟哥的私房菜基础篇第三版，知识很详细，这里就不多说了。
(1) 创建LVM
步骤一：再新建5块10MB SCSI的硬盘
这一步和上一步制作raid的操作是一样的，请参见上一篇
步骤二：用4块硬盘做raid5+1hostspare
mdadm --create --auto=yes /dev/md1 --level=5 --raid-devices=4 --spare-device=1 /dev/sdc{5,6,7,8,9}
注意：这次我们创建raid起名为/dev/md1(上次为/dev/md0)
步骤三：查看RAID组成情况
[root@compute-0 mnt]# mdadm --detail /dev/md*
mdadm: /dev/md does not appear to be an md device
/dev/md0: # 上次RAID实验创建的
Version : 1.2
Creation Time : Fri Mar 22 04:41:39 2013
Raid Level : raid5
Array Size : 480768 (469.58 MiB 492.31 MB)
Used Dev Size : 160256 (156.53 MiB 164.10 MB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Fri Mar 22 05:44:28 2013
State : clean
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Name : compute-0:0 (local to host compute-0)
UUID : d81cdfce:03d33c89:ffe54067:44e19b55
Events : 18
Number Major Minor RaidDevice State
0 8 21 0 active sync /dev/sdb5
1 8 22 1 active sync /dev/sdb6
2 8 23 2 active sync /dev/sdb7
5 8 24 3 active sync /dev/sdb8
4 8 25 - spare /dev/sdb9
/dev/md1: #这次我们新创建的
Version : 1.2
Creation Time : Fri Mar 22 04:42:44 2013
Raid Level : raid5
Array Size : 480768 (469.58 MiB 492.31 MB)
Used Dev Size : 160256 (156.53 MiB 164.10 MB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Fri Mar 22 05:44:31 2013
State : clean
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Name : compute-0:1 (local to host compute-0)
UUID : da3b02e6:b77652b6:3688ad25:9c34dabc
Events : 18
Number Major Minor RaidDevice State
0 8 37 0 active sync /dev/sdc5
1 8 38 1 active sync /dev/sdc6
2 8 39 2 active sync /dev/sdc7
5 8 40 3 active sync /dev/sdc8
4 8 41 - spare /dev/sdc9
步骤四：将RAID转换为物理卷(即：PV)
[root@compute-0 mnt]# pvscan # 先扫描一下是否有现存的物理卷
No matching physical volumes found
[root@compute-0 mnt]# pvcreate /dev/md1 # 创建物理卷
Writing physical volume data to disk "/dev/md1"
Physical volume "/dev/md1" successfully created
[root@compute-0 mnt]# pvscan # 查看一下
PV /dev/md1 lvm2 [469.50 MiB]
Total: 1 [469.50 MiB] / in use: 0 [0 ] / in no VG: 1 [469.50 MiB]
[root@compute-0 mnt]#
步骤五：新建一个逻辑卷组(即：VG)
[root@compute-0 mnt]# vgscan
Reading all physical volumes. This may take a while...
No volume groups found
[root@compute-0 mnt]# vgcreate -s 16M houqdvg /dev/md1
# 注：-s 表示PE的大小 houqdvg表示创建的逻辑卷组的名称
Volume group "houqdvg" successfully created
[root@compute-0 mnt]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "houqdvg" using metadata type lvm2
[root@compute-0 mnt]# vgdisplay
--- Volume group ---
VG Name houqdvg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 464.00 MiB
PE Size 16.00 MiB # PE的大小
Total PE 29 # 该逻辑卷组里面PE的总量
Alloc PE / Size 0 / 0
Free PE / Size 29 / 464.00 MiB
VG UUID vBlcd2-qt6Y-Bt1D-v63K-oIJv-a3Hm-tPzoue
[root@compute-0 mnt]#
步骤六：建立逻辑卷(即：LV)，并建立文件系统
[root@compute-0 mnt]# lvcreate -l 29 -n houqdlv houqdvg
注： -l 后面指定的是PE的个数
-L 后面指定的是按照大小来建
-n 后面指定创建的逻辑卷的名字
Logical volume "houqdlv" created
[root@compute-0 mnt]# lvdisplay
--- Logical volume ---
LV Name /dev/houqdvg/houqdlv
# 注：以后使用该逻辑卷一定要用这个/dev/houqdvg/houqdlv全名
VG Name houqdvg
LV UUID T0L4cu-dqNC-PRHz-QQ3u-0ubi-VAWe-YquY7t
LV Write Access read/write
LV Status available
# open 0
LV Size 464.00 MiB
Current LE 29
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 6144
Block device 253:0
[root@compute-0 mnt]# mkfs -t ext3 /dev/houqdvg/houqdlv # 创建文件系统
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=512 blocks, Stripe width=1536 blocks
118784 inodes, 475136 blocks
23756 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67633152
58 block groups
8192 blocks per group, 8192 fragments per group
2048 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 21 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@compute-0 mnt]#
步骤七：挂载逻辑卷，先用mount命令挂载，然后定义在/etc/fstab中
[root@compute-0 mnt]# mkdir -p /mnt/lvm
[root@compute-0 mnt]# mount /dev/houqdvg/houqdlv /mnt/lvm/ # 挂载
[root@compute-0 mnt]# mount # 查看所有挂载
/dev/sda2 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)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock (rw,nosuid,nodev,default_permissions,allow_other)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
/dev/mapper/houqdvg-houqdlv on /mnt/lvm type ext3 (rw) # 我们挂载的
[root@compute-0 mnt]# vi /etc/fstab # 设置每次开机自动挂载
# /etc/fstab
# Created by anaconda on Wed Feb 27 13:44:14 2013
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=4626a1a8-2485-4f14-a09a-6eef0a6c720e / ext4 defaults 1 1
UUID=74b536a0-9407-4214-98ed-11ba8b2d389c /boot ext4 defaults 1 2
UUID=a90215c9-be26-4884-bd0e-3799c7ddba7b swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/houqdvg/houqdlv /mnt/lvm ext3 defaults 1 2
(2) LVM扩容
步骤一：将第一个RAID转换为物理卷
[root@compute-0 mnt]# pvcreate /dev/md0
Writing physical volume data to disk "/dev/md0"
Physical volume "/dev/md0" successfully created
[root@compute-0 mnt]#
步骤二：将物理卷加入到现有的逻辑卷组中
[root@compute-0 mnt]# vgextend houqdvg /dev/md0
# 将/dev/md0加入到houqdvg这个卷组中了
Volume group "houqdvg" successfully extended
步骤三：查看逻辑卷组空间大小
[root@compute-0 mnt]# vgdisplay
--- Volume group ---
VG Name houqdvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 928.00 MiB
PE Size 16.00 MiB
Total PE 58 # 注：这里PE的总量增加了一倍，
Alloc PE / Size 29 / 464.00 MiB
Free PE / Size 29 / 464.00 MiB # 注：未分配的还有29个PE
VG UUID vBlcd2-qt6Y-Bt1D-v63K-oIJv-a3Hm-tPzoue
步骤四：将逻辑卷空间增加200M并查看逻辑卷空间大小
[root@compute-0 mnt]# lvdisplay
--- Logical volume ---
LV Name /dev/houqdvg/houqdlv
VG Name houqdvg
LV UUID T0L4cu-dqNC-PRHz-QQ3u-0ubi-VAWe-YquY7t
LV Write Access read/write
LV Status available
# open 1
LV Size 464.00 MiB # 这是未增加之前的
Current LE 29
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 6144
Block device 253:0
[root@compute-0 mnt]# lvresize -L +200M /dev/houqdvg/houqdlv
# 注：-L 后面直接指定大小，或者也可以用 -l+PE的个数来指定
Rounding up size to full physical extent 208.00 MiB
Extending logical volume houqdlv to 672.00 MiB
Logical volume houqdlv successfully resized
[root@compute-0 mnt]# lvdisplay
--- Logical volume ---
LV Name /dev/houqdvg/houqdlv
VG Name houqdvg
LV UUID T0L4cu-dqNC-PRHz-QQ3u-0ubi-VAWe-YquY7t
LV Write Access read/write
LV Status available
# open 1
LV Size 672.00 MiB # 可以看到该逻辑卷的确增加了200M
Current LE 42
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 6144
Block device 253:0
步骤五：将文件系统增加200M
[root@compute-0 mnt]# df /mnt/lvm/
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/houqdvg-houqdlv
460144 10543 425845 3% /mnt/lvm
# 注：我们已经将逻辑卷/dev/houqdvg/houqdlv扩容了但是这里还是400多M
[root@compute-0 mnt]# resize2fs /dev/houqdvg/houqdlv
# 注：这里才是真正的对文件系统扩容，实际block块的大小是不会增加的，只是分组数增多了，响应的空间就大了
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/houqdvg/houqdlv is mounted on /mnt/lvm; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 3
Performing an on-line resize of /dev/houqdvg/houqdlv to 688128 (1k) blocks.
The filesystem on /dev/houqdvg/houqdlv is now 688128 blocks long.
[root@compute-0 mnt]# df /mnt/lvm/
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/houqdvg-houqdlv
666415 10789 621236 2% /mnt/lvm
# 注：现在查看已经扩容
OK，这周的实验就先到这里吧，下周有可能会根据这两周做的实验，讲一下关于系统快照的知识，看情况再说吧。
