linux系统硬盘扩容

我的操作系统是centos7，硬盘使用的是vsan。
我把硬盘从40G扩容到100G。但是df -h后发现linux文件系统并没有识别到这新增加的60G。

[hyongtao@hyt-centos7-wdc ~]$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0  100G  0 disk
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0   39G  0 part
  ├─centos-root 253:0    0   37G  0 lvm  /
  └─centos-swap 253:1    0    2G  0 lvm  [SWAP]
sr0              11:0    1 1024M  0 rom
[hyongtao@hyt-centos7-wdc ~]$ df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 7.8G     0  7.8G   0% /dev
tmpfs                    7.8G   36K  7.8G   1% /dev/shm
tmpfs                    7.8G   18M  7.8G   1% /run
tmpfs                    7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/mapper/centos-root   37G  7.9G   30G  22% /
/dev/sda1               1014M  185M  830M  19% /boot
tmpfs                    1.6G   32K  1.6G   1% /run/user/1000
tmpfs                    1.6G     0  1.6G   0% /run/user/1002

我们观察一下sda，发现还有整整60G没有识别到。

NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0  100G  0 disk
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0   39G  0 part

考虑新增加一个分区，把剩下60G用上。主要使用命令fdisk。

[hyongtao@hyt-centos7-wdc ~]$ sudo 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): m
Command action
   p   print the partition table
   n   add a new partition
   w   write table to disk and exit (省略若干help信息，不同系统不一样。)

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 (83886080-209715199, default 83886080):
Using default value 83886080
Last sector, +sectors or +size{K,M,G} (83886080-209715199, default 209715199):
Using default value 209715199
Partition 3 of type Linux and of size 60 GiB is set

Command (m for help): p

Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos
Disk identifier: 0x000ac2dc

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     2099199     1048576   83  Linux
/dev/sda2         2099200    83886079    40893440   8e  Linux LVM
/dev/sda3        83886080   209715199    62914560   83  Linux        (识别到了sda3)

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)     (实测centos8上可以立即生效，不需要重启。)
Syncing disks.
[hyongtao@hyt-centos7-wdc ~]$

重启后，lsblk能识别到新的sda3，但是df-h还是没有识别到新的空间。

[hyongtao@hyt-centos7-wdc ~]$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0  100G  0 disk
├─sda1            8:1    0    1G  0 part /boot
├─sda2            8:2    0   39G  0 part
│ ├─centos-root 253:0    0   37G  0 lvm  /
│ └─centos-swap 253:1    0    2G  0 lvm  [SWAP]
└─sda3            8:3    0   60G  0 part              （新加的sd3,60G）
sr0              11:0    1 1024M  0 rom
[hyongtao@hyt-centos7-wdc ~]$ df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 7.8G     0  7.8G   0% /dev
tmpfs                    7.8G     0  7.8G   0% /dev/shm
tmpfs                    7.8G  9.8M  7.8G   1% /run
tmpfs                    7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/mapper/centos-root   37G  7.9G   30G  22% /
/dev/sda1               1014M  185M  830M  19% /boot
tmpfs                    1.6G   20K  1.6G   1% /run/user/1000
tmpfs                    1.6G     0  1.6G   0% /run/user/1002

随后的步骤可以参考这篇非常详细的博文：https://www.redhat.com/sysadmin/resize-lvm-simple ，以下内容是这篇博文的简单复现。

使用pvcreate和vgextend创建和扩大对应的物理卷

[hyongtao@hyt-centos7-wdc ~]$ sudo pvcreate /dev/sda3
[sudo] password for hyongtao:
  Physical volume "/dev/sda3" successfully created.
[hyongtao@hyt-centos7-wdc ~]$ sudo vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  centos   1   2   0 wz--n- <39.00g 4.00m
[hyongtao@hyt-centos7-wdc ~]$ sudo vgextend centos /dev/sda3
  Volume group "centos" successfully extended
[hyongtao@hyt-centos7-wdc ~]$ sudo vgs
  VG     #PV #LV #SN Attr   VSize  VFree
  centos   2   2   0 wz--n- 98.99g 60.00g

使用lvextend扩容逻辑卷

[hyongtao@hyt-centos7-wdc ~]$ sudo lvextend -l +100%FREE /dev/centos/root
  Size of logical volume centos/root changed from 36.99 GiB (9470 extents) to 96.99 GiB (24830 extents).
  Logical volume centos/root successfully resized.

使用xfs_growfs命令对xfs文件系统进行自动增容。

[hyongtao@hyt-centos7-wdc ~]$ sudo xfs_growfs /dev/centos/root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=2424320 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=9697280, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=4735, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 9697280 to 25425920

最后用df -h检查磁盘。

[hyongtao@hyt-centos7-wdc ~]$ df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 7.8G     0  7.8G   0% /dev
tmpfs                    7.8G     0  7.8G   0% /dev/shm
tmpfs                    7.8G  9.8M  7.8G   1% /run
tmpfs                    7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/mapper/centos-root   97G  7.9G   90G   9% /               (生效了)
/dev/sda1               1014M  185M  830M  19% /boot
tmpfs                    1.6G   20K  1.6G   1% /run/user/1000
tmpfs                    1.6G     0  1.6G   0% /run/user/1002

我对linux内核几乎毫无了解，这些东西都是这个大佬教我的，https://new.qq.com/rain/a/20201227A06AIT00 感谢，respect。现在做个记录怕忘了。

TODO：回头再鼓捣鼓捣这几个命令到底搞了什么鬼：pvcreate和vgextend和lvextend和xfs_growfs。还有物理卷和逻辑卷分别是什么意思？