Apple has provided a simple-to-use and effective backup application in all versions of OS X since Mac OS X v10.5. Time Machine was originally conceived to make it easy to back up computers with little effort. The process of setting up Time Machine is simply to connect an external hard drive and turn on Time Machine.
Time Machine has grown in capability and is a viable choice to back up OS X Server. Time Machine can be considered a form of continuous data protection, and it properly handles the databases OS X Server uses. Time Machine is the supported backup process for OS X Server.
If you have moved your service data off the startup volume, you need to refer to Apple Support article HT202406, "Restoring OS X Server from a Time Machine backup," for instructions on how to use command-line tools to restore the service data properly.
Backup targets for Time Machine are limited to hard drive volumes visible to the server and Time Machine–enabled network AFP share points.
For more information regarding Time Machine, refer to Lesson 16, "Time Machine," in Apple Pro Training Series: OS X Support Essentials 10.10.
Time Machine has the ability to back up to more than one target. This makes it easy to connect a hard drive to the server for continuous protection and connect a second drive that is rotated offsite. With two or more hard drives being rotated offsite, a disaster recovery plan can be implemented while providing instant recovery of data from the local drive as needed.
Time Machine is capable of taking snapshots and backing up onto its own startup volume. The snapshots feature is a convenience designed for laptops but shouldn't be considered for production servers.
Time Machine makes a backup once an hour for 24 hours. Beyond 24 hours it saves a daily backup for a month and then weekly backups from that point on until the target volume fills up. The oldest backups are deleted at that point. If you don't want to lose your backups, replace the backup targets as they become close to full.
One feature of Time Machine running on OS X Server is triggering a script that automatically archives the content of Open Directory each time Time Machine runs. The resulting file is placed in /private/var/backups/ and is copied along with other files during Time Machine operation. The archive can be recovered from that path in the backup location and used to re-create the Open Directory environment if required. To recover the file, you will need root access at the command line, and you will need to enable the root user and log in with the root credentials. See Apple Support article HT1528, "Enabling and using the 'root' user in Mac OS X," for more information.