First and foremost get familiar with a filesystem snapshot technology; whether an enterprise tool such as VMware's Veeam, or something like LVM. Secondly, get familiar with a replication technology of your database system, for example in MySQL we have master-master or master-slave.
The strategy can be explained in these simple terms is:
- Stop replication
- Stop database service on slave/secondary node
- Take a snapshot of the slave/secondary node
- Start replication
- Repeat steps 1 - 4 every hour
- Repeat steps 1 - 4 every day at midnight
- Repeat steps 1 - 4 every first day of the month at midnight
- Every Sunday at midnight, purge all hourly backups of the previous week
- Every first day of the month at midnight, purge all daily backups of the previous month excluding the first day
Now you have a nice catalog of backups which allow you to also do point-in-time recovery by applying binary logs in between backups. Adjust backup retention as necessary.