LVM管理设置

首先清楚一下LVM三个名词：PV-物理卷、 VG-卷组、 LV-逻辑卷
 
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[root@myserver root]# fdisk -l /dev/sda  --首先创建三个物理卷（这里我建好了，分别是sda5、sda6、sda7），创建为Linux LVM格式的，它的id是8e
Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot    Start       End    Blocks   Id  System
/dev/sda1   *         1       382   3068383+  83  Linux
/dev/sda2           383       764   3068415   83  Linux
/dev/sda3           765       802    305235   82  Linux swap
/dev/sda4           803      1044   1943865    5  Extended
/dev/sda5           803       815    104391   8e  Linux LVM
/dev/sda6           816       828    104391   8e  Linux LVM
/dev/sda7           829       841    104391   8e  Linux LVM

[root@myserver root]# pvcreate /dev/sda[5-7]   --初始化这三个物理卷
pvcreate -- physical volume "/dev/sda5" successfully created
pvcreate -- physical volume "/dev/sda6" successfully created
pvcreate -- physical volume "/dev/sda7" successfully created

[root@myserver root]# vgscan   --马上要创建卷组，不过记得第一次创建卷组前要执行vgscan
vgscan -- reading all physical volumes (this may take a while...)
vgscan -- "/etc/lvmtab" and "/etc/lvmtab.d" successfully created
vgscan -- WARNING: This program does not do a VGDA backup of your volume group

[root@myserver root]# vgcreate vg1 /dev/sda5 /dev/sda6  --创建卷组vg1，它包含两个物理卷sda5和sda6
vgcreate -- INFO: using default physical extent size 4 MB
vgcreate -- INFO: maximum logical volume size is 255.99 Gigabyte
vgcreate -- doing automatic backup of volume group "vg1"
vgcreate -- volume group "vg1" successfully created and activated
 
[root@myserver root]# vgdisplay vg1  --查看卷组vg1的信息
--- Volume group ---
VG Name               vg1 
VG Access             read/write
VG Status             available/resizable
VG #                  0
MAX LV                256
Cur LV                0
Open LV               0
MAX LV Size           255.99 GB  --扩展块为4MB时，逻辑卷最大支持255.99GB，可以通过定制扩展块大小修改它
Max PV                256
Cur PV                2
Act PV                2
VG Size               192 MB  --当前卷组空间大小（VG Size=PE Size*Total PE）
PE Size               4 MB  --最小扩展块（这里默认，可定制）
Total PE              48  --目前该卷组公分配了48个扩展块
Alloc PE / Size       0 / 0  --已经分配
Free  PE / Size       48 / 192 MB  --剩余分配
VG UUID               RVsKN4-Qx0K-OgFY-wCkX-qGKw-Y5BA-YtpEEd
 
[root@myserver root]#  lvcreate -n lv1 -L 20M vg1  --在卷组vg1上创建逻辑卷lv1，-n（命名），-L （制定逻辑卷大小），-L也可替换成-l（扩展块个数）
lvcreate -- doing automatic backup of "vg1"
lvcreate -- logical volume "/dev/vg1/lv1" successfully created

[root@myserver root]# mkfs.ext3 /dev/vg1/lv1  --对逻辑卷lv1进行格式化，然后才能进行挂载使用
mke2fs 1.32 (09-Nov-2002)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
--
--
--

[root@myserver root]# mount /dev/vg1/lv1 /mnt/lv1  --挂在到/mnt/lv1，就可以使用了
[root@myserver root]# lvdisplay /dev/vg1/lv1  --查看逻辑卷lv1的信息
--- Logical volume ---
LV Name                /dev/vg1/lv1
VG Name                vg1
LV Write Access        read/write
LV Status              available
LV #                   1
# open                 0
LV Size                20 MB  --大小，注意逻辑卷的大小只能是扩展块的倍数
Current LE             5  --当前扩展块倍数
Allocated LE           5
Allocation             next free
Read ahead sectors     1024
Block device           58:0

因为逻辑卷lv1是从卷组vg1上分出来的，这时我们再查看一下vg1，看有什么变化
[root@myserver root]# vgdisplay vg1
--- Volume group ---
VG Name               vg1
VG Access             read/write
VG Status             available/resizable
VG #                  0
MAX LV                256
Cur LV                1
Open LV               0
MAX LV Size           255.99 GB
Max PV                256
Cur PV                2
Act PV                2
VG Size               192 MB
PE Size               4 MB
Total PE              48
Alloc PE / Size       5 / 20 MB  --已经分出了5个扩展块，大小是4MB*5=20MB
Free  PE / Size       43 / 172 MB  --剩余可分的扩展块和总计大小
VG UUID               RVsKN4-Qx0K-OgFY-wCkX-qGKw-Y5BA-YtpEEd

[root@myserver root]# lvscan  --查看系统活动的逻辑卷，这里我只建了一个/dev/vg1/lv1
lvscan -- ACTIVE            "/dev/vg1/lv1" [20 MB]
lvscan -- 1 logical volumes with 20 MB total in 1 volume group
lvscan -- 1 active logical volumes
 
[root@myserver root]# e2fsadm -L +20M /dev/vg1/lv1  --将lv1容量增加20M,同理缩小容量就-20M；这里-L也可替换成-l，‘-l 10’和该条命令作用一致；
                                                                                   记得调整逻辑卷前要先卸掉啊；调整后可确认查看一下大小的变化
e2fsck 1.32 (09-Nov-2002)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg1/lv1: 11/5136 files (0.0% non-contiguous), 1696/20480 blocks
lvextend -- extending logical volume "/dev/vg1/lv1" to 40 MB
lvextend -- doing automatic backup of volume group "vg1"
lvextend -- logical volume "/dev/vg1/lv1" successfully extended
resize2fs 1.32 (09-Nov-2002)
Begin pass 1 (max = 2)
Extending the inode table     XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/vg1/lv1 is now 40960 blocks long.
e2fsadm -- ext2fs in logical volume /dev/vg1/lv1 successfully extended to 40 MB
 
[root@myserver root]# pvscan  --查看当前所有物理卷的状态，目前只有sda5和sda6在工作
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE   PV "/dev/sda5" of VG "vg1" [96 MB / 56 MB free]
pvscan -- ACTIVE   PV "/dev/sda6" of VG "vg1" [96 MB / 96 MB free]
pvscan -- inactive PV "/dev/sda7" is in no VG  [101.94 MB]
pvscan -- total: 3 [305.83 MB] / in use: 2 [203.89 MB] / in no VG: 1 [101.94 MB]
You have new mail in /var/spool/mail/root
 
[root@myserver root]# vgextend vg1 /dev/sda7  --再增加一个物理卷sda7到卷组，是其容量变大
vgextend -- INFO: maximum logical volume size is 255.99 Gigabyte
vgextend -- doing automatic backup of volume group "vg1"
vgextend -- volume group "vg1" successfully extended
 

刚才是增加一个物理卷到卷组，删除一个物理卷的话得先把该物理卷内的数据移动其他物理卷上，然后再移除该物理卷
[root@myserver root]# pvmove /dev/sda5  --把该物理卷内的数据移动其他物理卷上
pvmove -- moving physical extents in active volume group "vg1"
pvmove -- WARNING: if you lose power during the move you may need
        to restore your LVM metadata from backup!
pvmove -- do you want to continue? [y/n] y --确定
/dev/vg1/group::/dev/vg1/lv1: 0805 8576, 0806 8576
/dev/vg1/group::/dev/vg1/lv1: 0805 16768, 0806 16768
/dev/vg1/group::/dev/vg1/lv1: 0805 24960, 0806 24960
/dev/vg1/group::/dev/vg1/lv1: 0805 33152, 0806 33152
/dev/vg1/group::/dev/vg1/lv1: 0805 41344, 0806 41344
/dev/vg1/group::/dev/vg1/lv1: 0805 49536, 0806 49536
/dev/vg1/group::/dev/vg1/lv1: 0805 57728, 0806 57728
/dev/vg1/group::/dev/vg1/lv1: 0805 65920, 0806 65920
/dev/vg1/group::/dev/vg1/lv1: 0805 74112, 0806 74112
/dev/vg1/group::/dev/vg1/lv1: 0805 82304, 0806 82304
pvmove -- doing automatic backup of volume group "vg1"
pvmove -- 10 extents of physical volume "/dev/sda5" successfully moved
[root@myserver root]# vgreduce vg1 /dev/sda5  --然后再移除该物理卷，和vgextend功能相反
vgreduce -- doing automatic backup of volume group "vg1"
vgreduce -- volume group "vg1" successfully reduced by physical volume:
vgreduce -- /dev/sda5

[root@myserver root]# pvscan  --再次查看当前所有物理卷的状态，sda5已经不再卷组内了
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- inactive PV "/dev/sda5" is in no VG  [101.94 MB]
pvscan -- ACTIVE   PV "/dev/sda6" of VG "vg1" [96 MB / 56 MB free]
pvscan -- ACTIVE   PV "/dev/sda7" of VG "vg1" [96 MB / 96 MB free]
pvscan -- total: 3 [305.83 MB] / in use: 2 [203.89 MB] / in no VG: 1 [101.94 MB]
 
逻辑卷有一个有趣且实用的快照功能，拿来做备份还是很合适的，不过一经挂在就不能随意卸载，否则会停止备份工作
[root@myserver root]# lvcreate -s -L 40M -n snap /dev/vg1/lv1  --创建以lv1为快照对象的大小为40M的快照逻辑卷，不需要格式化，可直接挂在使用
lvcreate -- INFO: using default snapshot chunk size of 64 KB for "/dev/vg1/snap"
lvcreate -- doing automatic backup of "vg1"
lvcreate -- logical volume "/dev/vg1/snap" successfully created
 
 
删除逻辑卷和卷组
1，删除的顺序不能乱，先删除逻辑卷（注意有快照存在的情况下，先删除快照逻辑卷）、后删除卷组，这样物理卷才会全部被释放出来
2，卷组不能直接删除，得先将其设置为休眠状态，才可删
[root@myserver root]# lvscan  --先扫描一下都有哪些逻辑卷，当前有两个逻辑卷，其中以个快照snap
lvscan -- ACTIVE   Original "/dev/vg1/lv1" [40 MB]
lvscan -- ACTIVE   Snapshot "/dev/vg1/snap" [39.38 MB] of /dev/vg1/lv1
lvscan -- 2 logical volumes with 79.38 MB total in 2 volume groups
lvscan -- 2 active logical volumes
[root@myserver root]# lvremove /dev/vg1/snap  --删除快照逻辑卷
lvremove -- do you really want to remove "/dev/vg1/snap"? [y/n]: y  --确定删除
lvremove -- doing automatic backup of volume group "vg1"
lvremove -- logical volume "/dev/vg1/snap" successfully removed
[root@myserver root]# lvremove /dev/vg1/lv1  --删除逻辑卷lv1
lvremove -- do you really want to remove "/dev/vg1/lv1"? [y/n]: y  --确定删除
lvremove -- doing automatic backup of volume group "vg1"
lvremove -- logical volume "/dev/vg1/lv1" successfully removed
[root@myserver root]# vgchange -an vg1  --将vg1设置为休眠状态
vgchange -- volume group "vg1" successfully deactivated
[root@myserver root]# vgremove vg1  --删除卷组vg1
vgremove -- volume group "vg1" successfully removed
[root@myserver root]# pvscan  --这时所有物理卷都不属于任何卷组，都是‘自由’的了
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- inactive PV "/dev/sda5" is in no VG  [101.94 MB]
pvscan -- inactive PV "/dev/sda6" is in no VG  [101.94 MB]
pvscan -- inactive PV "/dev/sda7" is in no VG  [101.94 MB]
pvscan -- total: 3 [305.83 MB] / in use: 0 [0] / in no VG: 3 [305.83 MB]