LVM-HOWTO/学习笔记(一)

# dd if=/dev/zero of=/dev/diskname bs=1k count=1  删除硬盘

# blockdev --rereadpt /dev/diskname               重新读取硬盘分区表

在分区上创建pv

# vgcreate my_volume_group /dev/hda1 /dev/hdb1 

# vgchange -a y my_volume_group

先停用vg 

# vgchange -a n my_volume_group

然后移除

# vgremove my_volume_group

3)扩展vg

4)从vg中移除一个物理分区

   先要确认没有lv使用这个物理分区# pvdisplay /dev/hda1

--- Physical volume ---

PV Name               /dev/hda1

VG Name               myvg

PV Size               1.95 GB / NOT usable 4 MB [LVM: 122 KB]

PV#                   1

PV Status             available

Allocatable           yes (but full)

Cur LV                1

PE Size (KByte)       4096

Total PE              499

Free PE               0

Allocated PE          499

PV UUID               Sd44tK-9IRw-SrMC-MOkn-76iP-iftz-OVSen7

如果这个pv使用了，需要先使用pvmove命令转移数据到其他分区上

使用vgreduce命令移除物理分区

# vgreduce my_volume_group /dev/hda1

1)   创建

产生一个拥有100个LE,拥有2个条带，每个条带是4KB的lv

如果需要产生一个lv，使用整个VG，使用vgdiskplay命令，发现PE的总数，然后产生lv

# vgdisplay testvg | grep "Total PE"

Total PE              10230

# lvcreate -l 10230 testvg -n mylv

2)   移除

移除之前必须先关闭

# umount /dev/myvg/homevol

# lvremove /dev/myvg/homevol

lvremove -- do you really want to remove "/dev/myvg/homevol"? [y/n]: y

lvremove -- doing automatic backup of volume group "myvg"

lvremove -- logical volume "/dev/myvg/homevol" successfully removed

3)   扩展

扩展到12G

# lvextend -L12G /dev/myvg/homevol

lvextend -- extending logical volume "/dev/myvg/homevol" to 12 GB

lvextend -- doing automatic backup of volume group "myvg"

lvextend -- logical volume "/dev/myvg/homevol" successfully extended

加１G

# lvextend -L+1G /dev/myvg/homevol

lvextend -- extending logical volume "/dev/myvg/homevol" to 13 GB

lvextend -- doing automatic backup of volume group "myvg"

lvextend -- logical volume "/dev/myvg/homevol" successfully extended

默认的，扩展LV之后，需要扩展文件系统

除非安装了ext2的在线扩展补丁，否则需要先卸载挂载

# umount /dev/myvg/homevol/dev/myvg/homevol

   # resize2fs /dev/myvg/homevol

   # mount /dev/myvg/homevol /home

4)   缩减

先要缩减文件系统，然后缩减lv

Ext2

# umount /home

# resize2fs /dev/myvg/homevol 524288

# lvreduce -L-1G /dev/myvg/homevol

# mount /home

Reiserfs

# umount /home

# resize_reiserfs -s-1G /dev/myvg/homevol

# lvreduce -L-1G /dev/myvg/homevol

# mount -treiserfs /dev/myvg/homevol /home