In almost all cases, DigitalOcean will automatically take of everything when you resize your servers. On reboot, the disk is resized and Monit automatically picks up these changes. Nothing is required from you.
One of the great things about them is that everything just works. They’ve done a great job of making everything seamless when you scale your servers up and down.
In very, very rare circumstances though, their process may fail, and you will need to fix things over the command line.
Their official documentation can be found here:
https://docs.digitalocean.com/products/droplets/how-to/resize/
In it they state:
df -h after a disk resize and the output is unchanged, this usually indicates a problem. Resizing Disk Space Manually
Below we’ll follow DigitalOcean’s own guidance and examples from their documentation linked above.
Step 1. Check your disk space
Run the following to confirm that the disk has not been resized correctly:
df -h
The output will look something like the following:
root@server:~# df -h
Filesystem Size Used Avail Use% Mounted on
udev 979M 0 979M 0% /dev
tmpfs 199M 25M 3.2G 1% /run
/dev/vda1 25G 25G 0 100% /
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/loop0 33M 33M 0 100% /snap/snapd/12704
/dev/loop1 33M 33M 0 100% /snap/snapd/12398
/dev/loop2 62M 62M 0 100% /snap/core20/1026
/dev/loop3 43M 43M 0 100% /snap/certbot/1343
/dev/loop4 62M 62M 0 100% /snap/core20/1081
/dev/loop5 43M 43M 0 100% /snap/certbot/1280
/dev/vda15 105M 8.9M 96M 9% /boot/efi
tmpfs 199M 0 199M 0% /run/user/1003
tmpfs 199M 0 199M 0% /run/user/0Step 2. Verify available disk space
Use gdisk to get more information:
gdisk -l /dev/vda
The output looks like this:
GPT fdisk (gdisk) version 1.0.3
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Disk /dev/vda: 104857600 sectors, 50.0 GiB
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): C1E73477-225B-4585-8BB5-C9291E473CE4
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 52428766
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)
Number Start (sector) End (sector) Size Code Name
1 227328 52428766 24.9 GiB 8300Step 3. Resize Your Disk
To resize the partition, use the growpart command. /dev/vda is the name of the disk, separated by a space, and followed by the number of the partition to resize, 1.
growpart /dev/vda 1
Now resize the filesystem with:
resize2fs /dev/vda1
CHECK YOUR WORK
To confirm that our new disk space is available, run the following command again:
df -h
You’ll now see the new amount on this line of the output:
/dev/sda1 50G 25G 25G 50% /
Reload Monit
Now run the following to reload Monit and register the change:
monit reload