A MapR gateway mediates one-way communication between a source MapR cluster and a destination cluster. MapR-DB binary tables and MapR Streams streams can be replicated.
The initial task for setting up your gateways is to decide where you want to put your them.
- If you are going to replicate MapR-DB tables, see Gateways for Replicating MapR-DB Binary Tables.
- If you are going to replicate streams, see Gateways for Replicating MapR Streams Streams.
- If you are going to index MapR-DB binary tables to Elasticsearch, see Gateways for Indexing MapR-DB Data in Elasticsearch to find out where you can put gateways that you want to use for indexing.
However, the resource that gateways use the most is network bytes. For example, if the peak network throughput for puts is about 40 MB per second per node, in a 10-node source cluster the peak network throughput will be about 400 MB per second. So, the aggregate network throughput required on the nodes running gateways will be 400 MB per second for both incoming and outgoing traffic. The aggregate network throughput for a on 50 node cluster would be 2GB per second.
For another example, in this diagram there are two source clusters of three nodes each and the clusters are replicating to one destination cluster. The peak traffic on the gateways will be 40MB per second per cluster node, which means that these gateways together will experience a peak network load of 240MB per second.
Although the load is balanced across the two gateways, so that each gateway experiences a peak network load of 120MB per second, each gateway should be able to tolerate the full aggregate network load in case the other gateway fails unexpectedly.