Linux扩展根文件系统

Posted 2021-08-06 dingdingfish

有一个虚机模板，剩余空间不多了。于是在导入时指定了更大的根盘空间：100GB。

启动以后，可以看到盘确实变大了，但是接下来要扩展VG，LV和文件系统。

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_bigdatalite-lv_root
                       52G   39G   11G  79% /
tmpfs                  15G  1.2G   14G   9% /dev/shm
/dev/sda1             477M  204M  245M  46% /boot

$ lsblk
NAME                              MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                                 8:0    0  100G  0 disk
├─sda1                              8:1    0  500M  0 part /boot
├─sda2                              8:2    0 38.6G  0 part
│ ├─vg_bigdatalite-lv_root (dm-0) 249:0    0 52.5G  0 lvm  /
│ └─vg_bigdatalite-lv_swap (dm-1) 249:1    0  5.1G  0 lvm  [SWAP]
└─sda3                              8:3    0 19.5G  0 part
  └─vg_bigdatalite-lv_root (dm-0) 249:0    0 52.5G  0 lvm  /

可以看到新的sda有100G空间，所以第一步是利用其空闲空间建立新分区sda4。

# fdisk /dev/sda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Selected partition 4
First cylinder (7649-13054, default 7649):
Using default value 7649
Last cylinder, +cylinders or +size{K,M,G} (7649-13054, default 13054):
Using default value 13054

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.

需要将分区的类型改为LVM：

# fdisk /dev/sda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): t
Partition number (1-4): 4
Hex code (type L to list codes): 8e
Changed system type of partition 4 to 8e (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.

重启虚机。

看到我们的sda盘是这样的：

# fdisk -l
...
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        5100    40446976   8e  Linux LVM
/dev/sda3            5100        7648    20472560   8e  Linux LVM
/dev/sda4            7649       13054    43423695   8e  Linux LVM
...

首先建立PV:

# pvcreate /dev/sda4
  Physical volume "/dev/sda4" successfully created

然后利用这个PV，扩展VG：

# vgextend /dev/vg_bigdatalite /dev/sda4
  Volume group "vg_bigdatalite" successfully extended
# vgdisplay "vg_bigdatalite"
  --- Volume group ---
  VG Name               vg_bigdatalite
  System ID
  Format                lvm2
  Metadata Areas        3
  Metadata Sequence No  7
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                3
  Act PV                3
  VG Size               99.50 GiB
  PE Size               4.00 MiB
  Total PE              25472
  Alloc PE / Size       14738 / 57.57 GiB
  Free  PE / Size       10734 / 41.93 GiB
  VG UUID               OfvY4R-ZO5L-r6Rb-TwMF-qQBu-CEtK-vXdc33

# vgdisplay "vg_bigdatalite" | grep "Free"
  Free  PE / Size       10734 / 41.93 GiB

可以看到VG有剩余10734 个PE。

于是扩展LV：

# lvextend -l+10734 /dev/vg_bigdatalite/lv_root
  Size of logical volume vg_bigdatalite/lv_root changed from 52.49 GiB (13438 extents) to 94.42 GiB (24172 extents).
  Logical volume lv_root successfully resized.

# lvdisplay /dev/vg_bigdatalite/lv_root
  --- Logical volume ---
  LV Path                /dev/vg_bigdatalite/lv_root
  LV Name                lv_root
  VG Name                vg_bigdatalite
  LV UUID                8vebCn-nb0A-GtfY-fgZd-ET2E-hR0J-JKKh8a
  LV Write Access        read/write
  LV Creation host, time bigdatalite.localdomain, 2015-10-02 10:11:20 -0400
  LV Status              available
  # open                 1
  LV Size                94.42 GiB
  Current LE             24172
  Segments               3
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           249:0

扩展文件系统：

# resize2fs /dev/vg_bigdatalite/lv_root
resize2fs 1.43-WIP (20-Jun-2013)
Filesystem at /dev/vg_bigdatalite/lv_root is mounted on /; on-line resizing required
old_desc_blocks = 4, new_desc_blocks = 6
The filesystem on /dev/vg_bigdatalite/lv_root is now 24752128 blocks long.

成功了：

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_bigdatalite-lv_root
                       93G   39G   51G  44% /
tmpfs                  15G  1.2G   14G   9% /dev/shm
/dev/sda1             477M  204M  245M  46% /boot

参考

• https://kb.vmware.com/s/article/1006371
• https://www.howtoforge.com/logical-volume-manager-how-can-i-extend-a-volume-group

之前的笔记

补充一个最常用的扩充文件系统的场景：

1. extend disk in VMware Workstation(e.g. 2G)
2. boot VM, use fdisk /dev/sda to create a new primary partiton
3. reboot VM, then

[root@TTB ~]# fdisk -l|grep sda4
/dev/sda4            2872        3133     2104515   83  Linux
[root@TTB ~]# pvcreate /dev/sda4
  Physical volume "/dev/sda4" successfully created
[root@TTB ~]# vgextend VolGroup /dev/sda4
  Volume group "VolGroup" successfully extended

[root@TTB ~]# lvextend /dev/VolGroup/lv_root /dev/sda4
  Size of logical volume VolGroup/lv_root changed from 19.50 GiB (4991 extents) to 21.50 GiB (5504 extents).
  Logical volume lv_root successfully resized
[root@TTB ~]# resize2fs /dev/VolGroup/lv_root
resize2fs 1.43-WIP (20-Jun-2013)
Filesystem at /dev/VolGroup/lv_root is mounted on /; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 2
The filesystem on /dev/VolGroup/lv_root is now 5636096 blocks long.