Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache, and message broker.
It supports various data structures such as Strings, Hashes, Lists, Sets etc. DCOS offers Redis as a service.
Why Do We Use External Persistent Storage for Redis Mesos Containers?
Since Redis is an in-memory database, an instance/service restart will result in loss of data. To counter this, it is always advisable to snapshot the Redis in-memory database from time to time.
This helps Redis instance to recover from the point in time failure.