2.3減少LV的大小
2.3.1 查看/dev/sda5的PE數

[root@localhost ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda5
  VG Name               faqvg
  PV Size               1.87 GB / not usable 9.96 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              119
  Free PE               0
  Allocated PE          119
  PV UUID               gXmwpU-0oP0-YSmt-rpSd-qj5H-cEYf-1xBcky

2.3.2 降低LV的容量，已知/dev/sda5的PE數為119

[root@localhost ~]#  lvresize -l -119 /dev/faqvg/faqlv
  /dev/cdrom: open failed: Read-only file system
  WARNING: Reducing active and open logical volume to 9.30 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce faqlv? [y/n]: y
  Reducing logical volume faqlv to 9.30 GB
  Logical volume faqlv successfully resized
#會提示說實際資料量比9.30GB小，此部份就輸入y繼續吧。

2.3.3 查看LV總容量是否有變小

[root@localhost ~]#  lvdisplay
  --- Logical volume ---
  LV Name                /dev/faqvg/faqlv
  VG Name                faqvg
  LV UUID                QMOpsQ-3k87-BHSx-7crB-Wrlh-Zx11-Hn332K
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                9.30 GB
  Current LE             595
  Segments               5
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

2.4將PV移除VG之外
2.4.1 確認/dev/sda5的PE沒被使用才可移除

[root@localhost ~]#  pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda5
  VG Name               faqvg
  PV Size               1.87 GB / not usable 9.96 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              119
  Free PE               0
  Allocated PE          119
  PV UUID               gXmwpU-0oP0-YSmt-rpSd-qj5H-cEYf-1xBcky
--- Physical volume ---
  PV Name               /dev/sda9
  VG Name               faqvg
  PV Size               3.73 GB / not usable 12.11 MB
  Allocatable           yes 
  PE Size (KByte)       16384
  Total PE              238
  Free PE               119
  Allocated PE          119
  PV UUID               yxprOa-Gcvb-BHe8-LbOu-3Qxi-1sbC-WN3I4l
#發現到空閒的PE都在/dev/sda9，而/dev/sda5的PE都有在使用。因為要先搬移PE才可移除

2.4.2 搬移PE

[root@localhost ~]#  pvmove /dev/sda5 /dev/sda9
  /dev/sda5: Moved: 1.7%
  /dev/sda5: Moved: 100.0%
[root@localhost ~]# pvdisplay     #再次確PE數
  --- Physical volume ---
  PV Name               /dev/sda5
  VG Name               faqvg
  PV Size               1.87 GB / not usable 9.96 MB
  Allocatable           yes 
  PE Size (KByte)       16384
  Total PE              119
  Free PE               119
  Allocated PE          0
  PV UUID               gXmwpU-0oP0-YSmt-rpSd-qj5H-cEYf-1xBcky
--- Physical volume ---
  PV Name               /dev/sda9
  VG Name               faqvg
  PV Size               3.73 GB / not usable 12.11 MB
  Allocatable           yes (but full)
  PE Size (KByte)       16384
  Total PE              238
  Free PE               0
  Allocated PE          238
  PV UUID               yxprOa-Gcvb-BHe8-LbOu-3Qxi-1sbC-WN3I4l

2.4.3 從faqvg中移除/dev/sda5

[root@localhost ~]#  vgreduce  faqvg /dev/sda5
  /dev/cdrom: open failed: Read-only file system
  Removed "/dev/sda5" from volume group "faqvg"
[root@localhost ~]# pvscan
  PV /dev/sda6   VG faqvg           lvm2 [1.86 GB / 0    free]
  PV /dev/sda7   VG faqvg           lvm2 [1.86 GB / 0    free]
  PV /dev/sda8   VG faqvg           lvm2 [1.86 GB / 0    free]
  PV /dev/sda9   VG faqvg           lvm2 [3.72 GB / 0    free]
  PV /dev/sda5                      lvm2 [1.87 GB]
  Total: 5 [11.17 GB] / in use: 4 [9.30 GB] / in no VG: 1 [1.87 GB]

2.5從PV中移除partition

[root@localhost ~]#  pvremove /dev/sda5
  /dev/cdrom: open failed: Read-only file system
  Labels on physical volume "/dev/sda5" successfully wiped
[root@localhost ~]# pvscan  #查看PV會發現/dev/sda5已經被移除了。
  PV /dev/sda6   VG faqvg   lvm2 [1.86 GB / 0    free]
  PV /dev/sda7   VG faqvg   lvm2 [1.86 GB / 0    free]
  PV /dev/sda8   VG faqvg   lvm2 [1.86 GB / 0    free]
  PV /dev/sda9   VG faqvg   lvm2 [3.72 GB / 0    free]
  Total: 4 [9.30 GB] / in use: 4 [9.30 GB] / in no VG: 0 [0   ]

2.6刪除一個partition

[root@localhost ~]#  fdisk -l
/dev/sda5             798        1041     1959898+  83  Linux
#先查詢看看此partition是否存在
[root@localhost ~]# fdisk /dev/sda
Command (m for help): d
Partition number (1-9): 5
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
#提示設定需要重開機後才生效，若不想重開幾可使用partprobe(強制生效)
[root@localhost ~]# partprobe
[root@localhost ~]# fdisk -l
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14         666     5245222+  83  Linux
/dev/sda3             667         797     1052257+  82  Linux swap / Solaris
/dev/sda4             798        2610    14562922+   5  Extended
/dev/sda6            1042        1285     1959898+  83  Linux
/dev/sda7            1286        1529     1959898+  83  Linux
/dev/sda8            1530        1773     1959898+  83  Linux
/dev/sda9            1774        2260     3911796   83  Linux
#生效之後在查看一下會發現/dev/sda5已經完全被移除了。

LVM-LV的容量增減設定(上)
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