Introduction
Terraform Enterprise offers several configuration options to allow for a variety of use cases and business needs. When installing TFE you can choose between demo mode, mounted disk mode and external services mode.
Scenario
Demo mode should never be used for a live environment. Demo mode is not designed to allow for any recovery of data, unlike mounted disk and external services. This means that if you are running a demo mode instance of TFE with important information, all of that can easily be lost and unrecoverable.
Running an environment in mounted disk mode means that all of the data is stored locally on the TFE instance server. The data is seperated from the rest of the services in a way that it can be recovered (with the environment’s encryption password) in the case of an environment failure. Without the encryption password, the data is unrecoverable.
External services mode will allow for the TFE instance to run on one server and use an external source to store the data and database. This allows the data to be protected if the server hosting your TFE instance is ever compromised. Using external services also means that it will not encounter out of memory failures while trying to store logs and other data on a hard drive, because the data will instead go to an S3 bucket which is infinitely expandable.
Recommendation
Both mounted disk mode and external services mode are valid, and supported choices for running a production TFE environment. If the environment is small and tightly managed, mounted disk mode may be a good choice. However if there are any concerns about hard drive capacity or disaster recovery, external services will better protect your server and data.
Additional Information
This document is intended for customers running v4 Terraform Enterprise. Mounted Disk mode will not be available in v5 clustered Terraform Enterprise.