Linux LVM安全删除硬盘或分区--从根目录删除盘

LVM总共700G，其中sda系统盘，sdb 536G，sdc 214G，实际数据使用空间164G，想要缩减空间做删除盘的操作。

1、查看分区情况

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      7xxG  169G   xxG  65% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                 7.9G     0  7.9G   0% /dev/shm

说明：斜体表示不确定具体数据，仅供参考

# fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14        3916    31350847+  8e  Linux LVM

Disk /dev/sdb: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdc doesn't contain a valid partition table

由于是删除挂载在/目录的盘，不能在线删盘，需要进入安全模式

重启操作系统，从安装光盘启动

输入linux rescue 进入linux 安全模式，选择不挂载 NO-NO-NO

2、取消挂载，进行磁盘检测

lvm vgscan -v

lvm vgchange -a y

lvm lvs -all

e2 fsck -f  /dev/mapper/VolGroup00-LogVol00 磁盘检测

3、对逻辑卷重定义大小

resize2fs -p  /dev/mapper/VolGroup00-LogVol00 300G 重定义大小，缩至300G

lvreduce -L 310G  /dev/mapper/VolGroup00-LogVol00  重定义大小

由700G变成300G，大约要删除400G，就算400G的盘子数据满了，也可以全部移走。

4、查看物理卷情况

 pvdisplay -m
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               29.90 GB / not usable 24.06 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              956
  Free PE               0
  Allocated PE          956
  PV UUID               cjwiEg-ZlfV-e1q0-VqpF-whuF-BAq4-ECOsrx
   
  --- Physical Segments ---
  Physical extent 0 to 892:
    Logical volume      /dev/VolGroup00/LogVol00
    Logical extents     0 to 892
  Physical extent 893 to 955:
    Logical volume      /dev/VolGroup00/LogVol01
    Logical extents     0 to 62
   
  --- Physical volume ---
  PV Name               /dev/sdb
  VG Name               VolGroup00
  PV Size               500.00 GB / not usable 32.00 MB
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              15999
  Free PE               6972
  Allocated PE          9027
  PV UUID               ltIgU5-6uep-nusm-IvdZ-xby4-cVjT-2RQBrf
   
  --- Physical volume ---
  PV Name               /dev/sdc
  VG Name               VolGroup00
  PV Size               200.00 GB / not usable 32.00 MB
  Allocatable           yes  激活状态，可写入
  PE Size (KByte)       32768
  Total PE              15999  总共15999PE
  Free PE               15999  空闲15999PE，也就是说这块硬盘是空的
  Allocated PE          9027
  PV UUID               ltIgU5-6uep-nusm-IvdZ-xby4-cVjT-2RQBrf  
--- Physical Segments ---
  Physical extent 0 to 9026:
    Logical volume      /dev/VolGroup00/LogVol00
    Logical extents     893 to 9919
  Physical extent 9027 to 15998:
    FREE

5、移动数据，将要删除的盘的数据移动到别的盘

pvmove -i  /dev/sdc

no data to move for VolGroup00

这一步，非常重要，如果盘子里面有数据，不做这一步，会造成数据丢失

6、注销要删除的硬盘/dev/sdc

pvchange -xn /dev/sdc  注销sdc
pvdisplay -m
  --- Physical volume ---
  PV Name               /dev/sdc
  VG Name               VolGroup00
  PV Size               200.00 GB / not usable 32.00 MB
  Allocatable           NO   //不是激活状态了
  PE Size (KByte)       32768
  Total PE              15999   
  Free PE               15999 
  Allocated PE          0

7、将硬盘或分区从逻辑卷组中删除，并删除物理盘

vgreduce VolGroup00 /dev/sdc  //从逻辑卷组中删除

pvremove /dev/sdc   删除物理卷

pvdisplay 

sdc 已经看不到了。

8、查看结果

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                      291G  181G   96G  66% /
/dev/sda1              99M   13M   81M  14% /boot
tmpfs                 7.9G     0  7.9G   0% /dev/shm

启动数据库正常。主从复制线程正常(从)。

参考： http://blog.51yip.com/linux/1779.html