前段时间因为根磁盘 15GB 满了导致删除了很多文件，导致备份 磁盘 空闲下来，为避免根磁盘再次 被占满想把 备份磁盘扩容到根磁盘中

系统是按照自动分配磁盘安装的。 根 挂载在/dev/sda5下， 备份 挂载 /dev/sda3下。现在想把/dev/sda3合并到/dev/sda5中如何做？谢谢！

目前/dev/sda3已经格式化为ext4格式。

$ df -h

文件系统 容量 已用 可用 已用% 挂载点
udev 7.7G 0 7.7G 0% /dev
tmpfs 1.6G 1.8M 1.6G 1% /run
/dev/sda5 15G 9.7G 4.3G 70% /
tmpfs 7.7G 172M 7.5G 3% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 4.0M 0 4.0M 0% /sys/fs/cgroup
/dev/sda1 488M 160M 293M 36% /boot
/dev/sda7 376G 132G 226G 37% /data
tmpfs 1.6G 112K 1.6G 1% /run/user/1000
zlq@zlq:~$ sudo fdisk /dev/sda
请输入密码:
验证成功

Welcome to fdisk (util-linux 2.33.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p
Disk /dev/sda: 447.1 GiB, 480103981056 bytes, 937703088 sectors
Disk model: KINGSTON SV300S3
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: 0xcaa74e48

Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 1050623 1048576 512M 83 Linux
/dev/sda2 1050624 866398207 865347584 412.6G 5 Extended
/dev/sda3 866398208 904146943 37748736 18G 83 Linux
/dev/sda4 904146944 937701375 33554432 16G 82 Linux swap / Solaris
/dev/sda5 1052672 32507903 31455232 15G 83 Linux
/dev/sda6 32509952 63965183 31455232 15G 83 Linux
/dev/sda7 63967232 866398207 802430976 382.6G 83 Linux

Partition table entries are not in disk order.