Linux LVM逻辑卷配置过程详解（创建，增加，减少，删除，卸载）

http://dreamfire.blog.51cto.com/418026/1084729/
http://blog.csdn.net/beyondlpf/article/details/10147037
创建挂载目录

[root@localhost /]# mkdir data
[root@localhost /]# ls
bin boot data dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var

将物理硬盘分区初始化为物理卷，以便LVM使用
[root@localhost /]# pvcreate /dev/mapper/mpatha /dev/mapper/mpathb /dev/mapper/mpathc /dev/mapper/mpathd
WARNING: ext3 signature detected on /dev/mapper/mpatha at offset 1080. Wipe it? [y/n]: y
Wiping ext3 signature on /dev/mapper/mpatha.
Physical volume "/dev/mapper/mpatha" successfully created
Physical volume "/dev/mapper/mpathb" successfully created
Physical volume "/dev/mapper/mpathc" successfully created
Physical volume "/dev/mapper/mpathd" successfully created
使用pvs命令显示系统中所有物理卷的信息报表
[root@localhost /]# pvs
PV VG Fmt Attr PSize PFree
/dev/mapper/mpatha lvm2 --- 11.99t 11.99t
/dev/mapper/mpathb lvm2 --- 11.99t 11.99t
/dev/mapper/mpathc lvm2 --- 11.99t 11.99t
/dev/mapper/mpathd lvm2 --- 10.90t 10.90t
/dev/sda2 rhel00 lvm2 a-- 199.51g 60.00m
/dev/sdb3 rhel lvm2 a-- 4.17t 60.00m
pvdisplay命令显示的物理卷信息包括：物理卷名称、所属的卷组、物理卷大小、PE大小、总PE数、可用PE数、已分配的PE数和UUID
[root@localhost /]# pvdisplay
--- Physical volume ---

"/dev/mapper/mpathc" is a new physical volume of "11.99 TiB"
--- NEW Physical volume ---
PV Name /dev/mapper/mpathc
VG Name
PV Size 11.99 TiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID zGGvwF-o8iE-GQ80-0VaO-Yolt-ocMM-gcIRtT

"/dev/mapper/mpathb" is a new physical volume of "11.99 TiB"
--- NEW Physical volume ---
PV Name /dev/mapper/mpathb
VG Name
PV Size 11.99 TiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID eNkp1o-vJtJ-vZ7O-2Q8s-0SM5-1z7b-ElODOq

"/dev/mapper/mpathd" is a new physical volume of "10.90 TiB"
--- NEW Physical volume ---
PV Name /dev/mapper/mpathd
VG Name
PV Size 10.90 TiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID JHoNWp-5vFW-p4l4-kg1M-sM7F-wXIb-qaj0nI

"/dev/mapper/mpatha" is a new physical volume of "11.99 TiB"
--- NEW Physical volume ---
PV Name /dev/mapper/mpatha
VG Name
PV Size 11.99 TiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID BHAxua-l4CG-6EwP-fnkU-uMMp-yqUq-QLzMQ7
创建LVM卷组;卷组（Volume Group）将多个物理卷组织成一个整体，屏蔽了底层物理卷细节。在卷组上创建逻辑卷时不用考虑具体的物理卷信息。
[root@localhost /]# vgcreate vgdata /dev/mapper/mpatha /dev/mapper/mpathb /dev/mapper/mpathc /dev/mapper/mpathd
Volume group "vgdata" successfully created

查找系统中存在的LVM卷组，并显示找到的卷组列表
[root@localhost /]# vgs
VG #PV #LV #SN Attr VSize VFree
rhel 1 3 0 wz--n- 4.17t 60.00m
rhel00 1 3 0 wz--n- 199.51g 60.00m
vgdata 4 0 0 wz--n- 46.87t 46.87t
显示LVM卷组的信息。如果不指定"卷组"参数，则分别显示所有卷组的属性
[root@localhost /]# vgdisplay

--- Volume group ---
VG Name vgdata
System ID
Format lvm2
Metadata Areas 4
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 4
Act PV 4
VG Size 46.87 TiB
PE Size 4.00 MiB
Total PE 12286687
Alloc PE / Size 0 / 0
Free PE / Size 12286687 / 46.87 TiB
VG UUID f6KQNs-3Dl2-SZ8d-yn6j-7EGC-TiSN-NFXaVc

--- Volume group ---
VG Name rhel
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 4.17 TiB
PE Size 4.00 MiB
Total PE 1092752
Alloc PE / Size 1092737 / 4.17 TiB
Free PE / Size 15 / 60.00 MiB
VG UUID iex1R8-KJbM-EBRd-oZxh-QcUn-3c0r-Fr40pJ
创建LVM的逻辑卷;逻辑卷是创建在卷组之上的。逻辑卷对应的设备文件保存在卷组目录下，例如：在卷组"vg1000"上创建一个逻辑卷"lvol0"，则此逻辑卷对应的设备文件为"/dev/vg1000/lvol0"

[root@localhost /]# lvcreate -l 100%VG -n data_lv vgdata
Logical volume "data_lv" created.

格式化逻辑卷
[root@localhost /]# mkfs.ext4 /dev/vgdata/data_lv
mke2fs 1.42.9 (28-Dec-2013)
文件系统标签=
OS type: Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
786348032 inodes, 12581567488 blocks
629078374 blocks (5.00%) reserved for the super user
第一个数据块=0
383959 block groups
32768 blocks per group, 32768 fragments per group
2048 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848, 512000000, 550731776, 644972544, 1934917632,
2560000000, 3855122432, 5804752896

Allocating group tables: 完成
正在写入inode表: 完成
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成

将格式化后的逻辑卷挂载到已经创建的目录
[root@localhost /]# mount /dev/vgdata/data_lv /data/

查看逻辑卷与挂载目录的对应挂载信息
[root@localhost /]# mount|grep data
/dev/mapper/vgdata-data_lv on /data type ext4 (rw,relatime,data=ordered)
列出逻辑卷信息
[root@localhost /]# ll /dev/vgdata/data_lv
lrwxrwxrwx 1 root root 8 5月 2 11:14 /dev/vgdata/data_lv -> ../dm-10
[root@localhost /]# cd data/
[root@localhost data]# ls
lost+found

查看挂载后挂载目录的大小
[root@localhost data]# df -h /data/
文件系统 容量 已用 可用 已用% 挂载点
/dev/mapper/vgdata-data_lv 47T 20K 45T 1% /data

使用blkid命令对查询设备上所采用文件系统类型进行查询。blkid主要用来对系统的块设备（包括交换分区）所使用的文件系统类型、LABEL、UUID等信息进行查询。要使用这个命令必须安装e2fsprogs软件包。
[root@localhost dev]# blkid /dev/vgdata/data_lv
/dev/vgdata/data_lv: UUID="b2020adb-bfaa-46bf-bec8-0e4b3f238d43" TYPE="ext4"

启动自动挂载
[root@localhost data]# vim /etc/fstab
vim /etc/fstab
UUID="b2020adb-bfaa-46bf-bec8-0e4b3f238d43" /data ext4 defaults 0 0