怎样给centos系统扩展磁盘分区

问题/故障/场景/需求

eve-ng的虚拟机ova的硬盘只有38G，需要增加空间，在vmware直接扩展硬盘后，重启系统，使用fdisk -l可以看到硬盘扩大了，但文件系统并没有扩大，还需要将这些新增的空间扩展分配到某个文件系统才行。下面记录了整个扩展过程

解决方法/步骤

在VM里扩大磁盘到250G重启系统后，查看当前的文件系统的情况

root@eve-ng:~# df -h
Filesystem                    Size  Used Avail Use% Mounted on
udev                          7.9G     0  7.9G   0% /dev
tmpfs                         1.6G   19M  1.6G   2% /run
/dev/mapper/eve--ng--vg-root   38G   13G   23G  36% /
tmpfs                         7.9G     0  7.9G   0% /dev/shm
tmpfs                         5.0M     0  5.0M   0% /run/lock
tmpfs                         7.9G     0  7.9G   0% /sys/fs/cgroup
/dev/sda1                     472M   83M  365M  19% /boot

root@eve-ng:~# fdisk -l
...省略部分内容
Disk /dev/sda: 250 GiB, 268435456000 bytes, 524288000 sectors   //可以看到已经有250G了
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x3e3ca055

Device     Boot   Start      End  Sectors  Size Id Type
/dev/sda1  *       2048   999423   997376  487M 83 Linux
/dev/sda2       1001470 83884031 82882562 39.5G  5 Extended
/dev/sda5       1001472 83884031 82882560 39.5G 8e Linux LVM

Disk /dev/mapper/eve--ng--vg-root: 38.6 GiB, 41406169088 bytes, 80871424 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/eve--ng--vg-swap_1: 980 MiB, 1027604480 bytes, 2007040 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

//下面执行分区
root@eve-ng:~# fdisk /dev/sda

Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): n
Partition type
   p   primary (1 primary, 1 extended, 2 free)
   l   logical (numbered from 5)
Select (default p): p
Partition number (3,4, default 3): 3
First sector (999424-524287999, default 999424): 83884032 //注意，这里是之前分配的最后一块（sda5 end）加一（83884031+1）
Last sector, +sectors or +size{K,M,G,T,P} (83884032-524287999, default 524287999): //注意看这是不是最后一块

Created a new partition 3 of type 'Linux' and of size 210 GiB.

Command (m for help): t
Partition number (1-3,5, default 5): 3 3
Partition type (type L to list all types): 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.
Re-reading the partition table failed.: 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).

root@eve-ng:~# reboot

root@eve-ng:~# pvcreate /dev/sda3
  Physical volume "/dev/sda3" successfully created
root@eve-ng:~# vgdisplay
  --- Volume group ---
  VG Name               eve-ng-vg
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               39.52 GiB
  PE Size               4.00 MiB
  Total PE              10117
  Alloc PE / Size       10117 / 39.52 GiB
  Free  PE / Size       0 / 0
  VG UUID               EvwUbc-nfsg-dHqA-znxB-U3gv-V782-Q8ZxkI

root@eve-ng:~# vgextend eve-ng-vg /dev/sda3
  Volume group "eve-ng-vg" successfully extended
root@eve-ng:~# vgdisplay
  --- Volume group ---
  VG Name               eve-ng-vg
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               249.52 GiB
  PE Size               4.00 MiB
  Total PE              63877
  Alloc PE / Size       10117 / 39.52 GiB
  Free  PE / Size       53760 / 210.00 GiB
  VG UUID               EvwUbc-nfsg-dHqA-znxB-U3gv-V782-Q8ZxkI

root@eve-ng:~# lvdisplay
  --- Logical volume ---
  LV Path                /dev/eve-ng-vg/root
  LV Name                root
  VG Name                eve-ng-vg
  LV UUID                ktUpR0-VpqS-rJJv-a1FC-u6Gd-U8yN-2WYQ53
  LV Write Access        read/write
  LV Creation host, time eve-ng, 2018-03-21 02:25:21 +0200
  LV Status              available
  # open                 1
  LV Size                38.56 GiB
  Current LE             9872
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

//扩展逻辑卷
root@eve-ng:~# lvextend -l +100%FREE /dev/eve-ng-vg/root
  Size of logical volume eve-ng-vg/root changed from 38.56 GiB (9872 extents) to 248.56 GiB (63632 extents).
  Logical volume root successfully resized.

root@eve-ng:~# df -h
Filesystem                    Size  Used Avail Use% Mounted on
udev                          7.9G     0  7.9G   0% /dev
tmpfs                         1.6G   19M  1.6G   2% /run
/dev/mapper/eve--ng--vg-root   38G   13G   23G  36% /
tmpfs                         7.9G     0  7.9G   0% /dev/shm
tmpfs                         5.0M     0  5.0M   0% /run/lock
tmpfs                         7.9G     0  7.9G   0% /sys/fs/cgroup
/dev/sda1                     472M   83M  365M  19% /boot

//在线扩容,要先查看当前的文件系统的类型，可以通过cat /etc/fstab来查看
root@eve-ng:~# resize2fs /dev/eve-ng-vg/root
resize2fs 1.42.13 (17-May-2015)
Filesystem at /dev/eve-ng-vg/root is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 16
The filesystem on /dev/eve-ng-vg/root is now 65159168 (4k) blocks long.

root@eve-ng:~# df -h
Filesystem                    Size  Used Avail Use% Mounted on
udev                          7.9G     0  7.9G   0% /dev
tmpfs                         1.6G   19M  1.6G   2% /run
/dev/mapper/eve--ng--vg-root  245G   13G  222G   6% /
tmpfs                         7.9G     0  7.9G   0% /dev/shm
tmpfs                         5.0M     0  5.0M   0% /run/lock
tmpfs                         7.9G     0  7.9G   0% /sys/fs/cgroup
/dev/sda1                     472M   83M  365M  19% /boot