通过命令查看当前硬盘使用情况

[root@localhost zunmx]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0          11:0    1  8.6G  0 rom  /run/media/zunmx/CentOS-8-3-2011-x86_64-dvd
nvme0n1     259:0    0   30G  0 disk
├─nvme0n1p1 259:1    0    1G  0 part /boot
├─nvme0n1p2 259:2    0    2G  0 part [SWAP]
└─nvme0n1p3 259:3    0   17G  0 part /

发现硬盘30G，已用20G，那么接下来就分配剩下的10G给p3

分区扩容

[root@localhost zunmx]# fdisk /dev/nvme0n1

Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

# 查看分区信息
Command (m for help): p
Disk /dev/nvme0n1: 30 GiB, 32212254720 bytes, 62914560 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
Disklabel type: dos
Disk identifier: 0xb1bc7a59

Device         Boot   Start      End  Sectors Size Id Type
/dev/nvme0n1p1 *       2048  2099199  2097152   1G 83 Linux
/dev/nvme0n1p2      2099200  6293503  4194304   2G 82 Linux swap / Solaris
/dev/nvme0n1p3      6293504 41943039 35649536  17G 83 Linux

# 先删除目标分区p3，注意，先别w
Command (m for help): d
Partition number (1-3, default 3): 3

Partition 3 has been deleted.
# 创建分区，范围默认即可
Command (m for help): n
Partition type
   p   primary (2 primary, 0 extended, 2 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (3,4, default 3): 3
First sector (6293504-62914559, default 6293504): 
Last sector, +sectors or +size{K,M,G,T,P} (6293504-62914559, default 62914559): 

Created a new partition 3 of type 'Linux' and of size 27 GiB.
Partition #3 contains a xfs signature.
# 输入n
Do you want to remove the signature? [Y]es/[N]o: n

# 写入分区表
Command (m for help): w

The partition table has been altered.
Syncing disks.

重新读取分区表

[root@localhost zunmx]# partprobe /dev/nvme0n1

同步文件系统

[root@localhost zunmx]# xfs_growfs /dev/nvme0n1p3

检查分区扩容情况

[root@localhost zunmx]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0          11:0    1  8.6G  0 rom  /run/media/zunmx/CentOS-8-3-2011-x86_64-dvd
nvme0n1     259:0    0   30G  0 disk 
├─nvme0n1p1 259:1    0    1G  0 part /boot
├─nvme0n1p2 259:2    0    2G  0 part [SWAP]
└─nvme0n1p3 259:3    0   27G  0 part /

[root@localhost zunmx]# df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        362M     0  362M   0% /dev
tmpfs           391M     0  391M   0% /dev/shm
tmpfs           391M   12M  380M   3% /run
tmpfs           391M     0  391M   0% /sys/fs/cgroup
/dev/nvme0n1p3   27G  4.4G   23G  16% /
/dev/nvme0n1p1 1014M  235M  780M  24% /boot
tmpfs            79M  1.2M   77M   2% /run/user/42
tmpfs            79M  4.6M   74M   6% /run/user/1000

结语

事件原因未排版，操作分区有风险，需谨慎。