Xianbo QIAN
Feb 9 · 2 min read

How many time do you have to stop your VM and attach a new disk because you ran out of space when downloading a huge dataset or training a model.

Well, you don’t have to do so. Cloud computing has been evolving for many years and resize disk on the fly is now a trivial task for users to do. I believe Cloud provider has developed pretty advanced virtual disk technology, but I’ll skip that since I’m not an expert.

This post is a pretty short step-by-step guide on how to do so on Google Cloud Compute Engine. It only applies for arguably the most common case — The entire disk is reserved for a single partition /.

Step 0.1: Check remaining disks available

$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 77G 0 77G 0% /dev
tmpfs 16G 9.1M 16G 1% /run
/dev/sda1 970G 552G 418G 57% /
tmpfs 77G 228K 77G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 77G 0 77G 0% /sys/fs/cgroup

Line starting with /dev/sda1 is the one you’re looking for. From the example above, you notice that you have used more than half of the disk mounted as /

If you see the use rate is over 80%, that’s probably a dangerous sign.

Step 0.2: Check partition

$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 1000G 0 disk
└─sda1 8:1 0 1000G 0 part /

You noticed that device sda only contains one partition sda1, which made things much simpler.

Step 1: Increase disk size

In your VM . instance setting, click on the disk (either boot disk or additional disk), then increase the capacity by the amount you need.

Step 2: Grow the partition

Go to your VM console

$ sudo growpart /dev/sda 1
CHANGED: partition=1 start=2048 old: size=419428319 end=419430367 new: size=2097149919
,end=2097151967

Step 3: Resize file system

$ sudo resize2fs /dev/sda1
resize2fs 1.42.13 (17-May-2015)
Filesystem at /dev/sda1 is mounted on /; on-line resizing required
old_desc_blocks = 13, new_desc_blocks = 63
The filesystem on /dev/sda1 is now 262143739 (4k) blocks long.

Step 4: Verify

$ df -h

All done. Enjoy!

Google Cloud Platform - Community

A collection of technical articles published or curated by Google Cloud Platform Developer Advocates. The views expressed are those of the authors and don't necessarily reflect those of Google.

Xianbo QIAN

Written by

Google Cloud Platform - Community

A collection of technical articles published or curated by Google Cloud Platform Developer Advocates. The views expressed are those of the authors and don't necessarily reflect those of Google.

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