Redis:
     +--------------------+                                         log: /var/lib/redis/*.log
     |                    |                                         db: /data/redis/
     | redis1 {M}         |                                             (20GB){encrypted}...
     |  :6379             o----------+-------------------------+
     |                    |          |                         |  Sentinel:
     +-------------+------+          |                         |    quorum: 2
     | Sentinel1  :26379  |          |                         |    down-after-miliseconds: 3000
     +-------------+------+          |                         |
                             +-------o------------+            |
                             |                    |            |
                             | redis3 {S1}        |            |
                             |  :6379             |            |
                             |                    |            |
                             +-------------+------+            |
                             | Sentinel2  :26379  |            |
                             +-------------+------+            |
                                                     +---------o----------+
                                                     |                    |
                                                     | redis3 {S2}        |
                                                     |  :6379             |
                                                     |                    |
                                                     +-------------+------+
                                                     | Sentinel3  :26379  |
                                                     +-------------+------+