前两天在T2拿了一台新服务器，操作系统是Xen Server 5.6，默认情况下，他们将/dev/sda3和/dev/sdb2加到同一个LVM卷组，做为Xen Sever的Local Storage。但是因为实际应用需要，我需要将两个卷分开，操作步骤如下。

1、首先用vgdisplay查看LVM卷组名（VG Name）

[root@xen9 ~]# vgdisplay
— Volume group —
VG Name               VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e89905d71
System ID
Format                lvm2
Metadata Areas        2
Metadata Sequence No  4
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                1
Open LV               0
Max PV                0
Cur PV                2
Act PV                2
VG Size               874.65 GB
PE Size               4.00 MB
Total PE              223910
Alloc PE / Size       1 / 4.00 MB
Free  PE / Size       223909 / 874.64 GB
VG UUID               3efDeW-TvHK-dh66-yiFO-ljlV-5tS2-GaDYh2

2、用pvdisplay查看物理卷的具体情况

[root@xen9 ~]# pvdisplay
— Physical volume —
PV Name               /dev/sda3
VG Name               VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e89905d71
PV Size               457.76 GB / not usable 6.62 MB
Allocatable           yes
PE Size (KByte)       4096
Total PE              117183
Free PE               117182
Allocated PE          1
PV UUID               mGXYYK-OoM1-8ZRB-ilP0-h4CH-H4EV-pMcXzs

— Physical volume —
PV Name               /dev/sdb2
VG Name               VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e89905d71
PV Size               416.92 GB / not usable 22.51 MB
Allocatable           yes
PE Size (KByte)       4096
Total PE              106727
Free PE               106727
Allocated PE          0
PV UUID               s98dhd-bQ9o-XNcK-5Py8-6BgG-dzJw-wCvbo4

3、用vgreduce指令将/dev/sdb2从当前卷组中删除

[root@xen9 ~]# vgreduce VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e89905d71 /dev/sdb2
Removed “/dev/sdb2″ from volume group “VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e

4、用pvremove将/dev/hdb2的pv标记去除

[root@xen9 ~]# pvremove /dev/sdb2
Labels on physical volume “/dev/sdb2″ successfully wiped

5、再用pvdisplay查看物理卷的情况时，你会发现只有一个物理卷了。

[root@xen9 ~]# pvdisplay
— Physical volume —
PV Name               /dev/sda3
VG Name               VG_XenStorage-96cb10ab-23a5-5f94-5ef0-a51e89905d71
PV Size               457.76 GB / not usable 6.62 MB
Allocatable           yes
PE Size (KByte)       4096
Total PE              117183