LVM逻辑卷的创建、扩展、缩减和归纳

逻辑卷管理器LVM ：
LVM的优势：1、弹性存储 2、可以使用快照 LVM: 将几个物理分区通过软件组合在一起，看起来像是独立的大硬盘，而要用这块大硬盘，就要将它分成可以使用的分区，然后格式化，挂载等PV物理卷：将物理磁盘或物理分区初始化成LVM能用的物理卷，分区中的类型是8e:Linux LVMVG逻辑卷组：将一个或者多个PV组合成一个大的磁盘，将其称之为组
LV逻辑卷：从VG中分割出来的分区，称为LV，LV被用来格式化后，进行挂载，设备代为： /dev/vgname/lvname

相关命令整理

	创建	删除	查看	详细查看	移动	扩展	减少
PV	pvcreate	pvremove	pvs	pvdisplay	pvmove
VG	vgcreate	vgremove	vgs	vgdisplay	vgmove	vgextend	vgreduce
LV	lvcreate	lvremove	lvs	lvdisplay	lvmove	lvextend	lvreduce

注：举例：如果一个PV下有两个物理分区sda6和sda7，现分区空间过大一个sda6已经够用想把sda7拆下，

以下为创建一个LV的具体操作：

首先创建分区，sda6 sda7 这里分区的文件系统选择 8e Linux LVM ，

[root@bird 桌面]# pvcreate /dev/sda6 /dev/sda7WARNING: swap signature detected on /dev/sda6. Wipe it? [y/n]: y
Wiping swap signature on /dev/sda6.
Physical volume "/dev/sda6" successfully created
Physical volume "/dev/sda7" successfully created
[root@bird 桌面]# pvs 显示创建的pv
PV VG Fmt Attr PSize PFree
/dev/sda6 lvm2 --- 2.00g 2.00g
/dev/sda7 lvm2 --- 1.01g 1.01g
[root@bird 桌面]# pvdisplay 显示详细的pv信息
"/dev/sda6" is a new physical volume of "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sda6
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID itkIEM-poEM-FK3M-Ycoj-Fco1-S11Q-MXnlby

"/dev/sda7" is a new physical volume of "1.01 GiB"
--- NEW Physical volume ---
PV Name /dev/sda7
VG Name
PV Size 1.01 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID s9TdIp-v3hg-zYn3-BSJW-XDH2-wKXK-gXWJbW
[root@bird 桌面]# vgcreate zydata /dev/sda6 /dev/sda7 创建VG
Volume group "zydata" successfully created
[root@bird 桌面]# vgs 查看VG
VG #PV #LV #SN Attr VSize VFree
zydata 2 0 0 wz--n- 3.01g 3.01g
[root@bird 桌面]# vgdisplay 详细显示vg的信息
--- Volume group ---
VG Name zydata
System ID
Format lvm2
Metadata Areas 2
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 2
Act PV 2
VG Size 3.01 GiB
PE Size 4.00 MiB
Total PE 770
Alloc PE / Size 0 / 0
Free PE / Size 770 / 3.01 GiB
VG UUID iEZS4P-4jLo-dS4V-WwSJ-1lLo-73yd-i88tlv

[root@bird 桌面]# vgremove zydata 直接移除vg zydata
Volume group "zydata" successfully removed
[root@bird 桌面]# vgs
[root@bird 桌面]# vgcreate -s 8M zydata /dev/sda6 创建PE大小为8M的 默认为4M 这里仅指定了sda6
Volume group "zydata" successfully created
[root@bird 桌面]# vgdisplay
--- Volume group ---
VG Name zydata
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 2.00 GiB
PE Size 8.00 MiB
Total PE 256
Alloc PE / Size 0 / 0
Free PE / Size 256 / 2.00 GiB
VG UUID mqn1Hj-pGoD-WyZS-8kgq-unEd-R3dj-7pFLa1
扩展逻辑卷：
[root@bird 桌面]# vgextend zydata /dev/sda7 扩展一个sda7进去
Volume group "zydata" successfully extended
[root@bird 桌面]# vgs
VG #PV #LV #SN Attr VSize VFree
zydata 2 0 0 wz--n- 3.01g 3.01g
[root@bird 桌面]# vgdisplay
--- Volume group ---
VG Name zydata
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 3.01 GiB 加sda7之后大小变为3G (sda6为2G 7为1G
PE Size 8.00 MiB 之前定义过，则自动将新扩展进来的sda7的PE设置为8M.
Total PE 385
Alloc PE / Size 0 / 0
Free PE / Size 385 / 3.01 GiB
VG UUID mqn1Hj-pGoD-WyZS-8kgq-unEd-R3dj-7pFLa1
# pvmove /dev/sda7 先用pvmove将sda7中的数据复制出来,即可以将7中数据移到其他的分区中去)， [root@bird 桌面]# vgreduce zydata /dev/sda7 用vgreduce从zydata中将sda7除去 Removed "/dev/sda7" from volume group "zydata"[root@bird 桌面]# vgs VG #PV #LV #SN Attr VSize VFree zydata 1 0 0 wz--n- 2.00g 2.00g[root@bird 桌面]# pvs PV VG Fmt Attr PSize PFree /dev/sda6 zydata lvm2 a-- 2.00g 2.00g /dev/sda7 lvm2 --- 1.01g 1.01g sda7不属于任何VG [root@bird 桌面]# pvremove /dev/sda7 最后用pvremove 移除 Labels on physical volume "/dev/sda7" successfully wiped[root@bird 桌面]# pvs PV VG Fmt Attr PSize PFree /dev/sda6 zydata lvm2 a-- 2.00g 2.00g必须先将sda7数据move出来再用vgreduce除去sda7，最后才能pvremove来移除sda7，vgremove是用来移除vg的，vgreduce和vgextend是用来减少和增加分区的如：vgextend zydata /dev/sda7vgreduce zydata /dev/sda7[root@bird 桌面]# lvcreate -n testlv -L 1G zydata 创建大小为1G的lv
Logical volume "testlv" created.
[root@bird 桌面]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
testlv zydata -wi-a----- 1.00g
[root@bird 桌面]# lvdisplay
--- Logical volume ---
LV Path /dev/zydata/testlv 路径
LV Name testlv
VG Name zydata
LV UUID MMkFjJ-qlMN-ebQ1-eoBm-nxfz-nPtF-By8WU3
LV Write Access read/write
LV Creation host, time bird, 2017-04-19 15:03:47 +0800
LV Status available
# open 0
LV Size 1.00 GiB
Current LE 128
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
[root@bird 桌面]# mke2fs -j /dev/zydata/testlv 格式化lv
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=268435456
8 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376

正在写入inode表: 完成
Creating journal (8192 blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every 28 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@bird 桌面]# mkdir /mnt/test3
[root@bird 桌面]# mount /dev/zydata/testlv /mnt/test3/ 挂载lv
[root@bird 桌面]# ls /mnt/test3/
lost+found 挂载成功
[root@bird 桌面]# cp /etc/fstab /mnt/test3/ 测试
[root@bird 桌面]# cd /mnt/test3/
[root@bird test3]# cat fstab

#
# /etc/fstab
# Created by anaconda on Mon Feb 13 23:50:17 2017
#
# 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=43fa2114-8933-43bc-b4dc-d1d4811e7a64 / ext4 defaults 1 1
UUID=1ee52a34-d3a4-47f8-9863-f90aeeede43e /boot ext4 defaults 1 2
UUID=ea629952-0afa-45e9-bbb5-eb1dafa4cbc9 /home ext4 defaults 1 2
UUID=2aca97a2-9b18-41cb-9838-7a05b6fbf560 /usr ext4 defaults 1 2
UUID=7c374472-feea-47c6-a711-41a1d90b1bae 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/sda7 /mnt ext3 defaults 0 0
[root@bird ~]# lvextend -L +100M /dev/zydata/testlv 扩展lv，增加100M
Rounding size to boundary between physical extents: 104.00 MiB
Size of logical volume zydata/testlv changed from 1.00 GiB (128 extents) to 1.10 GiB (141 extents).
Logical volume testlv successfully resized
[root@bird ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
testlv zydata -wi-ao---- 1.10g
[root@bird ~]# resize2fs -p /dev/zydata/testlv 这是逻辑边界的扩展必须进行，否则df -h查看的话lv的扩展没有变化
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/zydata/testlv is mounted on /mnt/test3; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/zydata/testlv to 288768 (4k) blocks.
The filesystem on /dev/zydata/testlv is now 288768 blocks long.
[root@bird ~]# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 7.6G 411M 6.8G 6% /
tmpfs 504M 228K 503M 1% /dev/shm
/dev/sda1 1.9G 35M 1.8G 2% /boot
/dev/sda3 4.7G 336M 4.2G 8% /home
/dev/sda5 3.8G 3.2G 438M 89% /usr
/dev/sr0 3.6G 3.6G 0 100% /media/CentOS_6.7_Final
/dev/mapper/zydata-testlv
1.1G 34M 1021M 4% /mnt/test3 这里增加的100M就显示了
注意：扩展的话先lvextend 物理边界在resize2fs逻辑边界，可以在线扩展:
1、lvextend -L +100M /dev/zydata/testlv
2、/resize2fs -p /dev/zydata/testlv

缩减的话：1、不能在线缩减
2、必须先卸载，df -h确定已用的空间大于你要缩小的空间
3、e2fsck -f /dev/zydata/testlv 强行检查lv
4、resize2fs /dev/zydata/testlv —100M
5、lvreduce -L -100M /dev/zydata/testlv
（用法 resize2fs /dev/zydata/testlv —100M（不带加减号代表缩减至多少G）逻辑边界后，在用lvextend来缩减物理边界lvreduce -L -100M /dev/zydata/testlv
顺便补充一个快照卷的过程，
lvcreate -L 50M -s -p r -n kauizhao /dev/zydata/testlv
大小 -s指定创建快照 -p r指定只读 -n指定快照名 后面是lv的路径
至此一个完整的LVM的创建，扩展，缩减，以及要注意的地方都已经完成！OVER``````````