操作系统root目录磁盘分区扩容实践（无物理，逻辑卷）
环境说明：
虚拟机：vmware 16 play
操作系统：centos 8
1.虚拟机设置>目标磁盘>扩容磁盘容量（按需扩容磁盘大小）
2.查看磁盘空间大小
fdisk -l
[root@tertiary ~]# fdisk -l|more
Disk /dev/sda: 30 GiB, 32212254720 bytes, 62914560 sectors #当前磁盘大小30G
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: 0x68538fa9
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 616447 614400 300M 83 Linux
/dev/sda2 616448 4810751 4194304 2G 82 Linux swap / Solaris
/dev/sda3 4810752 41943039 37132288 17.7G 83 Linux #目标磁盘分区大小
3.查看文件系统大小
df -h
[root@tertiary ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 9.6M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda3 18G 17G 1.2G 94% / #目标文件大小
/dev/sda1 295M 173M 122M 59% /boot
tmpfs 371M 1.2M 370M 1% /run/user/42
tmpfs 371M 0 371M 0% /run/user/0
4.重新分配原有根目录目标磁盘分区（生产环境备份数据后执行操作）
fdisk /dev/sda
[root@tertiary ~]# fdisk /dev/sda
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.
Command (m for help): p #显示分区信息
Disk /dev/sda: 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: 0x68538fa9
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 616447 614400 300M 83 Linux
/dev/sda2 616448 4810751 4194304 2G 82 Linux swap / Solaris
/dev/sda3 4810752 41943039 37132288 17.7G 83 Linux
Command (m for help): d #删除分区
Partition number (1-3, default 3): 3 #删除3号分区
Partition 3 has been deleted.
Command (m for help): n #创建分区
Partition type
p primary (2 primary, 0 extended, 2 free)
e extended (container for logical partitions)
Select (default p): #创建主分区(默认)
Using default response p.
Partition number (3,4, default 3): #创建3号分区(必须与删除分区号相同)
First sector (4810752-62914559, default 4810752): #分区起始扇区
Last sector, +sectors or +size{K,M,G,T,P} (4810752-62914559, default 62914559): #分区结束扇区
Created a new partition 3 of type 'Linux' and of size 27.7 GiB.
Partition #3 contains a xfs signature.
Do you want to remove the signature? [Y]es/[N]o: y #移除标签
The signature will be removed by a write command.
Command (m for help): w #保存修改
The partition table has been altered.
Syncing disks.
5.检查磁盘分区大小变化
fdisk -l|more 或lsblk
[root@tertiary ~]# fdisk -l|more
Disk /dev/sda: 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: 0x68538fa9
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 616447 614400 300M 83 Linux
/dev/sda2 616448 4810751 4194304 2G 82 Linux swap / Solaris
/dev/sda3 4810752 62914559 58103808 27.7G 83 Linux #目标磁盘分区已扩容10G
6.查看文件系统类型
df -hT
[root@tertiary ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 9.6M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda3 xfs 18G 17G 1.2G 94% / #目标文件类型xfs
/dev/sda1 xfs 295M 173M 122M 59% /boot
tmpfs tmpfs 371M 1.2M 370M 1% /run/user/42
tmpfs tmpfs 371M 0 371M 0% /run/user/0
7.通过resize2fs或者xfs_growfs命令对文件系统进行扩容
上文检查文件类型为xfs，则用xfs_growfs命令执行操作
xfs_growfs /dev/sda3
[root@tertiary ~]# xfs_growfs /dev/sda3
meta-data=/dev/sda3 isize=512 agcount=4, agsize=1160384 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=4641536, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 4641536 to 7262976
8.确认文件系统大小
df -h
[root@tertiary ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 9.6M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda3 28G 17G 12G 60% / #目标文件系统已扩容10G
/dev/sda1 295M 173M 122M 59% /boot
tmpfs 371M 1.2M 370M 1% /run/user/42
tmpfs 371M 0 371M 0% /run/user/0
