The hardware requirements for your High Availability Add-on (HAA) are different between development and production environments.
Storage (default path
While one node is sufficient for a development environment, three or an odd number of nodes are recommended in order to utilize the clustering features likely needed for your production environment.
Cores per Node
Storage (default path
Note: Always maintain an odd number of nodes. This is required to obtain a quorum needed in failure and failover scenarios.
Default port used for internal proxy traffic.
Default port ranges used for internal cluster traffic.
Used for traffic from the application to the Discovery Service, if applicable.
8444 , 9080
Default ports used for internal
Default port used for internal CRDB (Conflict-free Replicated Database) traffic.
Used for metrics exported and managed by
Recommended port for REST API traffic.
Port range for database traffic. By default, HAA uses port
Port range used for internal database shards traffic.
Used for internal
HAA only supports 64-bit operating systems and must be installed on a clean host with no other applications. All HAA nodes must be synchronized with the same NTP server.
7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9
8.0, 8.1, 8.2, 8.3, 8.4
The HAA cluster needs three servers for a healthy operation.
Under normal circumstances, the HAA cluster servers have the following roles:
- one principal server – it holds a data shard, and it accepts read and write database operations from the outside world;
- one secondary server – it holds a copy of the data shard;
- one secondary server – it holds no data, it exists for quorum purposes only.
The HAA cluster supports a single server failure only.
- If one of the servers goes down, no matter which one, the HAA cluster continues working, and a warning is shown in the Web management interface. You can find more information by running the
rlcheckcommand, usually found in
/opt/redislabs/bin. You can also append
- If two servers fail, the HAA cluster fails as well, even if the principal server is still online.
Building an HAA cluster with more than three servers is possible but offers no real benefit.
There is no increase in the number of servers that can fail. In the case of a five-node HAA cluster, if the principal node and the secondary node keeping the data shard copy both fail, the entire cluster fails as well, and there is no data shard reallocation to other nodes.
HAA supports both IPv4 and IPv6. For more details on the support for multi-IP and IPv6, refer to Redis documentation.
Updated about a month ago