Google Cloud : check disk space usage

You can't see it in the disk preview as Faizan said, But you could Use Google StackDriver Monitoring tool to get a nice preview of your instances status.

The workaround with snapshot size will work in the console.

For more precise (and quicker) detailed overview you can SSH into your instance and do:

sudo df -h 

The response you get will look similar to this:

YOURUSERNAME@YOURINSTANCENAME:~$ sudo df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       9.8G  9.3G     0 100% /
udev             10M     0   10M   0% /dev
tmpfs           743M   81M  663M  11% /run
tmpfs           1.9G     0  1.9G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/sdb        197G   60M  197G   1% /mnt/new_disk

Entries starting with /dev/ under 'Filesystem' are your disks.

I use a simple workaround for this.

Create a snapshot of your persistent disk, and look at the snapshot size:

Just install Monitoring Agents in https://console.cloud.google.com/monitoring/dashboards/resourceList/gce_instance then check the dashboard