The most convenient form of encryption is disk/volume encryption. If you have any data on an existing Virtual Machine (VM), you can easily add an encrypted disk or volume. Then, when you unmount the encrypted volume (or power off the server), as long as you don't store the encryption key on the server, your data is safe.
The drawback with this type of encryption however is that if your server gets compromised somehow, there is a possibility that the attacker could capture your passphrase/key (and/or data) the next time you mount the disk image.
Incorrect:
Not C: Filesystem-level encryption, often called file/folder encryption, is a form of disk encryption where individual files or directories are encrypted by the file system itself. Each file can be and usually is encrypted with a separate encryption key.
References:
https://www.cloudsigma.com/securing-your-data-in-the-cloud-with-encryption/