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Linux 系统下给根分区扩容

来源：靑龍一笑的博客作者：靑龍一笑发布时间：2022-12-20 19:48:54 点击量：217 评论：0

近日，在进行服务器硬盘更换过程中，发现早期不合理的硬盘分区情况。

[root@RicenOS data]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 14G 1.3G 12G 10% /
tmpfs 499M 0 499M 0% /dev/shm
/dev/sda3 14G 316M 13G 3% /data
[root@RicenOS data]# fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000b98ad

Device Boot Start End Blocks Id System
/dev/sda1 1 262 2097152 82 Linux swap / Solaris
Partition 1 does not end on cylinder boundary.
/dev/sda2 * 262 2089 14679040 83 Linux
/dev/sda3 2089 3916 14678054 83 Linux

可以看到，/dev/sda1 是交换分区，/dev/sda2 是根分区，/dev/sda3 是一个数据分区。
现在要做的是，挂载一块新的硬盘，将数据分区上的数据拷贝到新硬盘上，然后将 /dev/sda2 和 /dev/sda3 这两个分区合并，以达到根分区扩容的目的。

[root@RicenOS ~]# fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000b98ad

Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

新硬盘是 /dev/sdb，创建一个目录用来挂载之前的数据分区，即 /dev/sda3。

[root@RicenOS ~]# mkdir -pv /old_data

卸载 /dev/sda3：

[root@RicenOS ~]# umount /data/

重新挂载 /dev/sda3：

[root@RicenOS ~]# mount /dev/sda3 /old_data/

对新硬盘进行 lvm 分区，并挂载到 /data 目录上，详细的操作请参考我的另一篇文章《给 Linux 系统添加新硬盘，并创建 LVM 分区》。

[root@RicenOS ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 14G 1.3G 12G 10% /
tmpfs 499M 0 499M 0% /dev/shm
/dev/sda3 14G 316M 13G 3% /old_data
/dev/mapper/data-data 7.8G 18M 7.4G 1% /data

将旧数据迁移到新硬盘上：

[root@RicenOS ~]# ls /data/
lost+found
[root@RicenOS ~]# ls /old_data/
lost+found ricen_file
[root@RicenOS ~]# mv /old_data/ricen_file/ /data/
[root@RicenOS ~]# ls /data/
lost+found ricen_file
[root@RicenOS ~]# ls /old_data/
lost+found

卸载旧分区：

[root@RicenOS ~]# umount /old_data/

删除没用的挂载点：

[root@RicenOS ~]# rm -rf /old_data/

扩容根分区：

[root@RicenOS ~]# fdisk -cu /dev/sda
Command (m for help): p

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 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
Disk identifier: 0x000b98ad

Device Boot Start End Blocks Id System
/dev/sda1 2048 4196351 2097152 82 Linux swap / Solaris
/dev/sda2 * 4196352 33554431 14679040 83 Linux
/dev/sda3 33554432 62910539 14678054 83 Linux

Command (m for help): d
Partition number (1-4): 3

Command (m for help): d
Partition number (1-4): 2

Command (m for help): p

Device Boot Start End Blocks Id System
/dev/sda1 2048 4196351 2097152 82 Linux swap / Solaris

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First sector (4196352-62914559, default 4196352):
Using default value 4196352
Last sector, +sectors or +size{K,M,G} (4196352-62914559, default 62914559):
Using default value 62914559

Command (m for help): p

Device Boot Start End Blocks Id System
/dev/sda1 2048 4196351 2097152 82 Linux swap / Solaris
/dev/sda2 4196352 62914559 29359104 83 Linux

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: 设备或资源忙.
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.

重启服务器：

[root@RicenOS ~]# reboot

调整 /dev/sda2 分区大小：

[root@RicenOS ~]# resize2fs /dev/sda2
[root@RicenOS ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 28G 1.3G 25G 5% /
tmpfs 499M 0 499M 0% /dev/shm
/dev/mapper/data-data 7.8G 299M 7.1G 4% /data