By default, 4 instances of Redis run, to provide resilience and alternative storage methods. They are not set up to be highly available/replicated.
They each are configured with 16 databases and no authentication.
Host: redis1.i Port: 6379 Recommend Use: Sessions Host: redis21.i Port: 6380 Recommend Use: N/A Domain: redis11.i Port: 6379 Recommend Use: Cache Domain: redis31.i Port: 6380 Recommend Use: FPC
Identifying Redis DBs in use
You can verify what Redis databases are currently being used by executing the following script,
Domain-Group Domain Session Cache FPC ============ ====== ======= ===== === example example.com redis1.i:0 redis11.i:0 x