linux入门书籍推荐|linux入门学习笔记

更新时间:2017-06-09    来源:基础入门    手机版     字体:

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lvm logical volumn manager 逻辑卷管理

可以自由增大或者缩小卷空间的大小

pv physical volumn(物理卷) 把实际分区设备划为pv , pv是lvm物理标记

vg volumn group (卷组) 把pv划分成vg,相当于组合成lvm能够使用一个大硬盘

pe physical extend (物理扩展)vg组成的最小单位,默认是4M,vg最大支持65535个pe,相当于是block

lv logical volumn (逻辑卷) 实际可以使用的lvm的设备,相当是把vg划分成可用的分区

1,划分pv
创建pv使用pvcreate命令
[root@dns ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
[root@dns ~]# pvcreate /dev/sdc1
Physical volume "/dev/sdc1" successfully created
[root@dns ~]# pvcreate /dev/md1
Physical volume "/dev/md1" successfully created

查看相关信息的命令 pvscan pvdisplay

删除pv的命令 pvremove /dev/sdb1

2,划分vg

[root@dns ~]# vgcreate li /dev/md1 --创建一个叫li的vg,把/dev/md1加进去
Volume group "li" successfully created

[root@dns ~]# vgextend li /dev/sdb1 --再入li这个vg增加pv,要用vgextend
Volume group "li" successfully extended
[root@dns ~]# vgextend li /dev/sdc1
Volume group "li" successfully extended

查看相关信息的命令vgscan vgdisplay

[root@dns ~]# vgreduce li /dev/sdc1 --vgreduce跟vgextend是相反的,是在vg里移除pv
Removed "/dev/sdc1" from volume group "li"

移除vg的命令是vgremove,它是和vgcreate相反

3,创建lv

[root@dns ~]# lvcreate -L 500m -n li01 li --在li这个vg里划分出一个叫li01的lv,大小为500m
Logical volume "li01" created
[root@dns ~]# lvcreate -L 500M -n li02 li
Logical volume "li02" created
[root@dns ~]# lvcreate -l 125 -n li03 li -- 小写l参数指定的是pe的个数,这里4M*125=500m
Logical volume "li03" created
[root@dns ~]# lvcreate -L 1g -n aa01 aa
Logical volume "aa01" created

查看的相关参数为lvscan lvdisplay

[root@dns ~]# lvscan --创建后,可以看到这些实际可用的lv存放在/dev/vg名/lv名
ACTIVE "/dev/aa/aa01" [1.00 GB] inherit
ACTIVE "/dev/li/li01" [500.00 MB] inherit
ACTIVE "/dev/li/li02" [500.00 MB] inherit
ACTIVE "/dev/li/li03" [500.00 MB] inherit

[root@dns ~]# mkfs.ext3 /dev/aa/aa01 --格式化lv后就可以挂载使用

移除lv使用lvremove

完全删除lvm,就要先lvremove,再vgremove,最后pvremove

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lv的扩容

1,先考虑vg是否还有空间去扩容,如果没有,那么要先扩容vg,使用vgextend

2,扩lv
[root@dns ~]# lvextend -L 1.5g /dev/aa/aa01 --把/dev/aa/aa01的lv扩成1.5g
Extending logical volume aa01 to 1.50 GB
Logical volume aa01 successfully resized

[root@dns ~]# df -h
Filesystem Size Used Avail Use% Mounted on

/dev/mapper/aa-aa01 1008M 34M 924M 4% /mnt --查看已经挂载的大小,没有变化

[root@dns ~]# resize2fs /dev/aa/aa01 --再使用这个命令去在线同步
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/aa/aa01 is mounted on /mnt; on-line resizing required
Performing an on-line resize of /dev/aa/aa01 to 393216 (4k) blocks.
The filesystem on /dev/aa/aa01 is now 393216 blocks long.

[root@dns ~]# df -h
Filesystem Size Used Avail Use% Mounted on

/dev/mapper/aa-aa01 1.5G 34M 1.4G 3% /mnt --再次查看,已经挂载的lv扩大了,并且数据没有影响

下面两种写法也可以
[root@dns ~]# lvextend -L +100M /dev/aa/aa01
[root@dns ~]# lvextend -l +25 /dev/aa/aa01

lv的缩小

[root@dns ~]# resize2fs /dev/aa/aa01 1g --这样去缩小的话,报错已经mount了
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/aa/aa01 is mounted on /mnt; on-line resizing required
On-line shrinking from 444416 to 262144 not supported.

[root@dns ~]# umount /mnt/

[root@dns ~]# resize2fs /dev/aa/aa01 1g --umount后再使用resize2fs命令,要求先去e2fsck检测
resize2fs 1.39 (29-May-2006)
Please run "e2fsck -f /dev/aa/aa01" first.

[root@dns ~]# e2fsck -f /dev/aa/aa01

[root@dns ~]# resize2fs /dev/aa/aa01 1g --检测后再使用resize2fs命令缩小,并挂载查看大小是否缩小

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