LVM创建实例及相关注释

[root@localhost ~]# fdisk /dev/sdb
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-130, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-130, default 130): +999M


Command (m for help): t ##指定类型
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): w 保存退出
The partition table has been altered!


然后依次对sdc sdd sde做一样的操作


[root@localhost ~]# fdisk -l|grep "^/dev/sd"
/dev/sda1 * 1 39 307200 83 Linux
/dev/sda2 39 2358 18631680 83 Linux
/dev/sda3 2358 2611 2031616 82 Linux swap / Solaris
/dev/sdb1 1 128 1028128+ 8e Linux LVM
/dev/sdc1 1 128 1028128+ 8e Linux LVM
/dev/sdd1 1 128 1028128+ 8e Linux LVM
/dev/sde1 1 128 1028128+ 8e Linux LVM
以上红色显示的是即将用于创建lvm的分区

[root@localhost ~]# pvcreate /dev/sd{b,c,d,e}1 创建 PV
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdc1" successfully created
Physical volume "/dev/sdd1" successfully created
Physical volume "/dev/sde1" successfully created


[root@localhost ~]# pvs 查看pv
PV VG Fmt Attr PSize PFree
/dev/sdb1 lvm2 a– 1004.03m 1004.03m
/dev/sdc1 lvm2 a– 1004.03m 1004.03m
/dev/sdd1 lvm2 a– 1004.03m 1004.03m
/dev/sde1 lvm2 a– 1004.03m 1004.03m


[root@localhost ~]# pvdisplay 相对pvs来说显示的更详细，以下是/dev/sdb1的显示内容
"/dev/sdb1" is a new physical volume of "1004.03 MiB"
— NEW Physical volume —
PV Name /dev/sdb1
VG Name
PV Size 1004.03 MiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 8etjmo-mVi0-ncst-Em9d-pMW0-z0Ol-q4fX8v


pvremove /dev/sdb1 即可删除
pvcreate /dev/sdb1 则可再加进来

[root@localhost ~]# vgcreate myvg /dev/sd{b,c,d}1 这里我们先加进来3块盘，另一块用于演示其他操作
Volume group "myvg" successfully created
如果要修改PE大小：可以使用-s参数 默认是4m
查看
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
myvg 3 0 0 wz–n- 2.93g 2.93g
[root@localhost ~]# vgdisplay 同样也比vgs显示的详细
— Volume group —
VG Name myvg
System ID
Format lvm2
Metadata Areas 3
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 3
Act PV 3
VG Size 2.93 GiB
PE Size 4.00 MiB
Total PE 750
Alloc PE / Size 0 / 0
Free PE / Size 750 / 2.93 GiB
VG UUID hbiddu-b9z4-WTxe-CwYK-WrNu-J0Af-tgLWZR
[root@localhost ~]# vgextend myvg /dev/sde1 添加硬盘到vg 增加磁盘没什么风险
Volume group "myvg" successfully extended
[root@localhost ~]# vgs 刚才是3个pv 现在4个且容量也增加了
VG #PV #LV #SN Attr VSize VFree
myvg 4 0 0 wz–n- 3.91g 3.91g
下面是移除磁盘，这是我没要考虑是否磁盘上有数据，如果有移到其他pv，然后移除
[root@localhost ~]# pvmove /dev/sdb1 ##移走数据
No data to move for myvg
[root@localhost ~]# vgreduce myvg /dev/sdb1 ##mypv移除/dev/sdb1
Removed "/dev/sdb1" from volume group "myvg"
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
myvg 3 0 0 wz–n- 2.93g 2.93g

[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
myvg 4 0 0 wz–n- 3.91g 3.91g
我们查看一共有不到4G的空间，创建的lv大小不能超过上面vg的大小
[root@localhost ~]# lvcreate -L 2G -n mylv myvg ##在myvg上创建一个mylv的逻辑卷大小2G
Logical volume "mylv" created[root@localhost ~]# lvs #查看
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
mylv myvg -wi-a—– 2.00g
[root@localhost ~]# lvdisplay 查看
— Logical volume —
LV Path /dev/myvg/mylv
LV Name mylv
VG Name myvg
LV UUID PPPW3e-xAiz-CMNM-RV2o-i8H1-yfIB-9g4KG2
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2015-06-06 21:24:36 -0700
LV Status available
# open 0
LV Size 2.00 GiB
Current LE 512
Segments 3
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:0
lv的访问路径：(此两者均为符号链接，指向的文件为/dev/dm-#)
1./dev/VG_name/LV_name
/dev/myvg/mylv
2./dev/mapper/VG_name-LV_name
/dev/mapper/myvg-mylv
[root@localhost ~]# ll /dev/dm-*
brw-rw—- 1 root disk 253, 0 Jun 6 21:24 /dev/dm-0
[root@localhost ~]# ll /dev/myvg/
lrwxrwxrwx 1 root root 7 Jun 6 21:24 mylv -> ../dm-0
[root@localhost ~]# ll /dev/mapper
lrwxrwxrwx 1 root root 7 Jun 6 21:24 myvg-mylv -> ../dm-0


lv创建好就是一个文件系统，我们就可以使用它了
[root@localhost ~]# mke2fs -t ext4 /dev/myvg/mylv
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131072 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
格式化后创建目录挂载吧：
[root@localhost ~]# mkdir /mnt/mylv
[root@localhost ~]# mount /dev/myvg/mylv /mnt/mylv
[root@localhost ~]# mount
/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)
/dev/mapper/myvg-mylv on /mnt/mylv type ext4 (rw)
如果想要长期使用，命令挂载只是暂时的，还要添加到/etc/fstab文件中最后一行增加：
/dev/myvg/mylv /mnt/mylv ext4 defaults 0 0
pv总空间为3.91G，现在只划给mylv 2G空间，如果不够用可以扩展mylv
1. lvextend 扩展物理边界
[root@localhost ~]# lvextend -L 3G /dev/myvg/mylv ###这里表示扩展到3G

Extending logical volume mylv to 3.00 GiB

Logical volume mylv successfully resized


[root@localhost ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda2 18G 2.9G 14G 18% /

tmpfs 495M 0 495M 0% /dev/shm

/dev/sda1 291M 34M 242M 13% /boot

/dev/mapper/myvg-mylv 2.0G 67M 1.9G 4% /mnt/mylv

2.resizefs 扩展逻辑边界
[root@localhost ~]# resize2fs /dev/myvg/mylv ###这里表示扩展至物理边界大小
resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/myvg/mylv is mounted on /mnt/mylv; on-line resizing required

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of /dev/myvg/mylv to 786432 (4k) blocks.

The filesystem on /dev/myvg/mylv is now 786432 blocks long.


[root@localhost ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda2 18G 2.9G 14G 18% /

tmpfs 495M 0 495M 0% /dev/shm

/dev/sda1 291M 34M 242M 13% /boot

/dev/mapper/myvg-mylv 3.0G 67M 2.8G 3% /mnt/mylv

[root@localhost ~]# e2fsck -f /dev/myvg/mylv

e2fsck 1.41.12 (17-May-2010)

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/myvg/mylv: 11/196608 files (0.0% non-contiguous), 29500/786432 blocks

[root@localhost ~]# resize2fs /dev/myvg/mylv 1G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/myvg/mylv to 262144 (4k) blocks.

The filesystem on /dev/myvg/mylv is now 262144 blocks long.

[root@localhost ~]# lvreduce -L 1G /dev/myvg/mylv

WARNING: Reducing active logical volume to 1.00 GiB

THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce mylv? [y/n]: y

Reducing logical volume mylv to 1.00 GiB

Logical volume mylv successfully resized
[root@localhost ~]# mount /dev/myvg/mylv /mnt/mylv
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 18G 2.9G 14G 18% /
tmpfs 495M 0 495M 0% /dev/shm
/dev/sda1 291M 34M 242M 13% /boot
/dev/mapper/myvg-mylv 1008M 67M 891M 7% /mnt/mylv

注意：快照卷是对某逻辑卷
[root@localhost ~]# mount -o remount,ro /dev/myvg/mylv /mnt/mylv ##先改成只读
[root@localhost ~]# lvcreate -L 1G -n mylv-snap -p r -s /dev/myvg/mylv ##对mylv做快照为mylv-snap 大小为1G
[root@localhost ~]# mount -o remount,rw /dev/myvg/mylv /mnt/mylv #快照完，立刻改为读写或者一个命令行直接执行者三个命令，或者写脚本
Logical volume "mylv-snap" created


[root@localhost ~]# mount /dev/myvg/mylv-snap /mnt/snap/ 挂载快照
mount: block device /dev/mapper/myvg-mylv–snap is write-protected, mounting read-only

如果不想用了，要删除怎么办？？
umount /mnt/snap
lvremove /dev/myvg/mylv-snap

另外还有：pvremove vgremove等删除命令，可以用man 查看