重做LVM文件系统之减小PV

命令

缩小PV空间到120G，即PV上的vg00已将缩小到120G
    pvresize --setphysicalvolumesize 120g /dev/sda2

背景

机器上有一块900G本地的本地磁盘，安装系统时将900G的空间全部扩到了一个VG卷组中，即vg00，并创建了多个LV逻辑卷，LV逻辑卷占用了vg00卷组120G的空间，即卷组vg00还剩770G左右的空闲空间；此种文件系统格式不符合应用的规范标准，标准的文件系统规范为创建一个120G的卷组Vg00，使用Vg00卷组创建系统必要的LV逻辑卷，而剩下的770G空间新建卷组Vg01。为了满足应用需求，现将900G盘上的vg00空间缩小为120G，然后新建vg01使用剩下的770G空间。在不影响系统正常的情况下实现PV/VG的缩小。由于LV占用了120G的VG，即将VG空间缩小到120G方可最大化利用vg00卷组，为了达到缩小Vg00的需求，通过缩小PV来强制缩小Vg空间。

操作流程

现有文件系统

[root@sishb00302 ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree
  vg00   1   6   0 wz--n- 837.84g 721.84g
[root@sishb00302 ~]# lvs
  LV       VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  crashvol vg00 -wi-ao---- 32.00g
  homevol  vg00 -wi-ao----  2.00g
  rootvol  vg00 -wi-ao---- 20.00g
  swapvol  vg00 -wi-ao---- 32.00g
  tmpvol   vg00 -wi-ao---- 10.00g
  varvol   vg00 -wi-ao---- 20.00g 

[root@sishb00302 ~]# fdisk /dev/sda
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p

Disk /dev/sda: 900.2 GB, 900151926784 bytes, 1758109232 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 262144 bytes / 262144 bytes
Disk label type: dos
Disk identifier: 0x000cd03d

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048  1758107647   878540800   8e  Linux LVM

减小PV

[root@sishb00302 ~]# pvresize --setphysicalvolumesize 120g /dev/sda2
  Physical volume "/dev/sda2" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized
[root@sishb00302 ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree
  vg00   1   6   0 wz--n- 120.00g 4.00g
[root@sishb00302 ~]# pvs
  PV         VG   Fmt  Attr PSize   PFree
  /dev/sda2  vg00 lvm2 a--  120.00g 4.00g

删除原有的900G的/dev/sda2分区，新建/dev/sda2分区为120G，剩余空间为/dev/sda3分区

[root@sishb00302 ~]# fdisk /dev/sda
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p

Disk /dev/sda: 900.2 GB, 900151926784 bytes, 1758109232 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 262144 bytes / 262144 bytes
Disk label type: dos
Disk identifier: 0x000cd03d

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048  1758107647   878540800   8e  Linux LVM

Command (m for help): d
Partition number (1,2, default 2):
Partition 2 is deleted

Command (m for help): n
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p):
Using default response p
Partition number (2-4, default 2):
First sector (1026048-1758109231, default 1026048):
Using default value 1026048
Last sector, +sectors or +size{K,M,G} (1026048-1758109231, default 1758109231): +120G
Partition 2 of type Linux and of size 120 GiB is set

Command (m for help): t
Partition number (1,2, default 2):
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): n
Partition type:
   p   primary (2 primary, 0 extended, 2 free)
   e   extended
Select (default p):
Using default response p
Partition number (3,4, default 3):
First sector (252684288-1758109231, default 252684288):
Using default value 252684288
Last sector, +sectors or +size{K,M,G} (252684288-1758109231, default 1758109231):
Using default value 1758109231
Partition 3 of type Linux and of size 717.9 GiB is set

Command (m for help): t
Partition number (1-3, default 3):
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

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 or after you run partprobe(8) or kpartx(8)
Syncing disks.

移除/dev/vg00/crashvol文件系统

[root@sishb00302 ~]# umount /var/crash/
[root@sishb00302 ~]# lvremove /dev/vg00/crashvol
Do you really want to remove active logical volume vg00/crashvol? [y/n]: y
  Logical volume "crashvol" successfully removed
[root@sishb00302 ~]# lvs
  LV      VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  homevol vg00 -wi-ao----  2.00g
  rootvol vg00 -wi-ao---- 20.00g
  swapvol vg00 -wi-ao---- 32.00g
  tmpvol  vg00 -wi-ao---- 10.00g
  varvol  vg00 -wi-ao---- 20.00g
[root@sishb00302 ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree
  vg00   1   5   0 wz--n- 120.00g 36.00g

/dev/vg00/varvol逻辑卷在线扩容

[root@sishb00302 ~]# lvextend -L +30g /dev/vg00/varvol -r
  Size of logical volume vg00/varvol changed from 20.00 GiB (5120 extents) to 50.00 GiB (12800 extents).
  Logical volume vg00/varvol successfully resized.
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/mapper/vg00-varvol is mounted on /var; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 7
The filesystem on /dev/mapper/vg00-varvol is now 13107200 blocks long.

[root@sishb00302 ~]# lvs
  LV      VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  homevol vg00 -wi-ao----  2.00g
  rootvol vg00 -wi-ao---- 20.00g
  swapvol vg00 -wi-ao---- 32.00g
  tmpvol  vg00 -wi-ao---- 10.00g
  varvol  vg00 -wi-ao---- 50.00g

修改fatab文件

修改前
[root@sishb00302 ~]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Tue Mar  6 11:44:46 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg00-rootvol /                       ext4    defaults        1 1
UUID=c04bb69b-1380-4c31-b4f4-9bfacb5d9063 /boot                   ext4    defaults        1 2
/dev/mapper/vg00-homevol /home                   ext4    defaults        1 2
/dev/mapper/vg00-tmpvol /tmp                    ext4    defaults        1 2
/dev/mapper/vg00-varvol /var                    ext4    defaults        1 2
/dev/mapper/vg00-crashvol /var/crash              ext4    defaults        1 2
/dev/mapper/vg00-swapvol swap                    swap    defaults        0 0

 修改后
[root@sishb00302 ~]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Tue Mar  6 11:44:46 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg00-rootvol /                       ext4    defaults        1 1
UUID=c04bb69b-1380-4c31-b4f4-9bfacb5d9063 /boot                   ext4    defaults        1 2
/dev/mapper/vg00-homevol /home                   ext4    defaults        1 2
/dev/mapper/vg00-tmpvol /tmp                    ext4    defaults        1 2
/dev/mapper/vg00-varvol /var                    ext4    defaults        1 2
/dev/mapper/vg00-swapvol swap                    swap    defaults        0 0

关机重启系统，从而释放/Idev/sda3分区的空间

空间释放后，再次创建vg01卷组

[root@sishb00302 ~]# lvs
  LV      VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  homevol vg00 -wi-ao----  2.00g
  rootvol vg00 -wi-ao---- 20.00g
  swapvol vg00 -wi-ao---- 32.00g
  tmpvol  vg00 -wi-ao---- 10.00g
  varvol  vg00 -wi-ao---- 50.00g                                                    

[root@sishb00302 ~]# vgcreate /dev/vg01 /dev/sda3
  Physical volume "/dev/sda3" successfully created.
  Volume group "vg01" successfully created
[root@sishb00302 ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree
  vg00   1   5   0 wz--n- 120.00g   6.00g
  vg01   1   0   0 wz--n- 717.84g 717.84g

[root@sishb00302 ~]# lvs
  LV      VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  homevol vg00 -wi-ao----  2.00g
  rootvol vg00 -wi-ao---- 20.00g
  swapvol vg00 -wi-ao---- 32.00g
  tmpvol  vg00 -wi-ao---- 10.00g
  varvol  vg00 -wi-ao---- 50.00g

最终实现了vg00文件系统从900G减小到了120G，并新建了vg01卷组