Ubuntu系统根分区已满，如何从/home分区扩容根分区？

Absolutely doable, and you’re smart to hold off on reinstalling while you’re in the middle of NVIDIA/CUDA driver debugging—let’s walk through the safe way to reallocate that space without disrupting your setup.

Critical Pre-Requisite: Backup Your Data #

Partition operations carry inherent risk (e.g., power loss mid-process can corrupt files). Backup all important data from your /home partition first. You can use an external drive and run this command from your active system (before booting into live mode):

rsync -av /home/ /path/to/external-drive/home-backup/

This creates an exact copy of your home directory, so you’ll have a fallback if anything goes wrong.

Step 1: Create a Ubuntu Live USB #

You can’t modify mounted partitions (your root and /home are mounted while the system is running), so you’ll need to boot from a live environment:

• Download the same Ubuntu version you’re using
• Use the built-in Startup Disk Creator (search for it in your applications menu) to make a bootable USB drive

Step 2: Boot into the Live Environment #

• Restart your computer and select the USB drive as the boot device (press F12, F2, or Del to access the boot menu, depending on your motherboard)
• Choose the "Try Ubuntu" option (don’t select "Install Ubuntu")

Step 3: Use GParted to Resize Partitions #

GParted is a user-friendly graphical partition editor pre-installed in the live session:

1. Open GParted (search for it in the live session’s application menu)
2. Select your main disk from the top-right dropdown (usually /dev/sda for HDDs or /dev/nvme0n1 for SSDs)
3. Shrink the /home partition:
   • Right-click your /home partition (look for the "home" label) and select Unmount (you can’t resize a mounted partition)
   • Right-click again and choose Resize/Move
   • Drag the right edge of the partition bar left to free up ~100GB of unallocated space
   • Click the green checkmark (Apply) to run the shrink operation
4. Expand the root partition:
   • Find your root partition (labeled "/" or no label, usually the first partition)
   • Right-click it and select Unmount
   • Right-click again and choose Resize/Move
   • Drag the right edge of the partition bar all the way right to absorb the unallocated space
   • Click Apply to run the expand operation
5. Wait for all operations to finish—don’t interrupt the process!

Step 4: Verify and Reboot #

• Once GParted confirms all tasks are done, close the program
• Reboot your computer and remove the USB drive
• Log back into your system, then run this command to check the new partition sizes:

df -h

You should see your root partition now has ~120GB of space, and /home has ~100GB left.

Edge Case Note #

If your partitions use LVM (Logical Volume Manager), the steps will differ slightly—you’ll need to use lvresize commands instead of GParted. Let me know if that’s your setup and I can walk you through it.

内容的提问来源于stack exchange，提问作者Joel Andersson