按如下操作

查看卷組相關信息

 [root@MyCloudServer ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "Xvdbgroup" using metadata type lvm2
  Found volume group "centos" using metadata type lvm2

查看卷組VolGroup00包含的PV、LV信息。

[root@MyCloudServer ~]# vgdisplay -v Xvdbgroup
    Using volume group(s) on command line.
  --- Volume group ---
  VG Name               Xvdbgroup
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               30.00 GiB
  PE Size               4.00 MiB
  Total PE              7679
  Alloc PE / Size       7655 / 29.90 GiB
  Free  PE / Size       24 / 96.00 MiB
  VG UUID               PBc5Xq-pQ61-L618-h8Nd-31oE-RmuB-qlaEyv
     --- Logical volume ---
  LV Path                /dev/Xvdbgroup/xvdb1
  LV Name                xvdb1
  VG Name                Xvdbgroup
  LV UUID                vgJbGW-UZAe-zM8y-HRcE-c5f6-PKpk-mh3lPU
  LV Write Access        read/write
  LV Creation host, time MyCloudServer, 2018-12-09 20:12:17 +0800
  LV Status              available
  # open                 1
  LV Size                29.90 GiB
  Current LE             7655
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2

  --- Physical volumes ---
  PV Name               /dev/xvdb1     
  PV UUID               ht2z0o-yINv-08WR-crWy-oeff-PXh6-IOGbMK
  PV Status             allocatable
  Total PE / Free PE    7679 / 24
 

卸載卷組上的邏輯卷LV
要卸載對應卷組VG的所有邏輯卷LV。從上面的信息可以看出對應的卷組VolGroup00只有/dev/VolGroup00/iscsi00這個邏輯卷LV

[root@MyCloudServer ~]# umount /dev/Xvdbgroup/xvdb1

刪除邏輯卷LV

[root@MyCloudServer ~]# lvremove /dev/Xvdbgroup/xvdb1 
Do you really want to remove active logical volume xvdb1? [y/n]: y
  Logical volume "xvdb1" successfully removed

刪除卷組VG

[root@MyCloudServer ~]# vgremove Xvdbgroup
  Volume group "Xvdbgroup" successfully removed

驗證卷組（VG）是否刪除 剩下centos 卷組是對的

[root@MyCloudServer ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "centos" using metadata type lvm2

刪除物理卷PV

[root@MyCloudServer ~]# pvremove /dev/xvdb1 
  Labels on physical volume "/dev/xvdb1" successfully wiped
 

編輯 /etc/fstab 刪除對應掛載點信息
這裏沒有安裝nano yum install nano 筆者喜歡用nano

[root@MyCloudServer ~]# nano /etc/fstab 
-bash: nano: command not found
[root@MyCloudServer ~]# yum install nano

看到/etc/fstab裏面沒有什麽需要刪的，Ctrl+C退出nano不用保存，
下面是格式化/dev/xvdb為ext4的格式

    [root@MyCloudServer ~]# mkfs.ext4 /dev/xvdb
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1966080 inodes, 7864320 blocks
393216 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2155872256
240 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
4096000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   

接下來就可以用一健腳本完成掛載

yum install wget -y && wget -O auto_disk.sh http://download.bt.cn/tools/auto_disk.sh && bash auto_disk.sh

可以查看df 和nano /etc/fstab 有沒有成功，成功了就可以reboot了

下次重裝時只選擇格式化系統盤，再次掛載數據不會丟失
mkdir /www
mount /dev/xvdb1 /www
echo "/dev/xvdb1 /www ext4 defaults 1 3" >> /etc/fstab
以上命令可以重新掛載/www分區，如果你是小白，數據很重要，建議備份了再試。

CentOS 7 刪除LV VG卷組邏輯卷物理卷