Setting Up Stream Replication Using the CLI

You can run the maprcli stream replica autosetup command to set up master-slave or multi-master replication from an existing source stream.

Note: This procedure describes how to use the maprcli to automatically set up stream replication. As an alternative, you can use the MapR Control Service (MCS) to automatically set up table replication or use the maprcli to manually set up master-slave replication.

Before you begin, review the following requirements:

You must replicate all of the topics that are in a stream. You cannot select only a subset of topics to replicate.
The maximum number of replicas that a stream can replicate to is 64.
The maximum number of upstream sources that a replica can accept data from is 64.
In multi-master replication, names of topics must be unique on all streams. Messages are assigned sequential offsets. The offsets for messages in a topic in one copy could conflict with the offsets for messages in the other copy. As a result, messages could be lost.
In many-to-one replication, topics with the same name should not be replicated to an aggregate replica.

In general, you should store your streams on their own volumes to avoid overlap with volume mirroring. Otherwise, if a source volume fails, you may have a scenario where a stream in the promoted mirror lags behind the stream's replica. See Preparing Clusters for Table Replication for more details.

Set up replication automatically by following these steps:

Log into both the source and destination clusters.
Run the command maprcli stream replica autosetup:
- For master-slave replication:
```
maprcli stream replica autosetup -path <path to source stream> -replica <path to replica stream>
```
  For example, to set up master-slave replication from the activity stream in the sanfrancisco cluster to a new activity stream in the newyork cluster, you could use this command:
```
maprcli stream replica autosetup -path 
/mapr/sanfrancisco/activity -replica /mapr/newyork/activity
```
- For multi-master replication:
```
maprcli stream replica autosetup -path <path to source stream> -replica <path to replica stream> -multimaster yes
```
  For example, to set up multi-master replication between the activity stream in the sanfrancisco cluster and a new activity stream in the newyork cluster, you could use this command:
```
maprcli stream replica autosetup -path /mapr/sanfrancisco/activity 
-replica /mapr/newyork/activity -multimaster yes
```
  Note: The parameter -multimaster is an optional parameter that you use to set up multimaster replication.
Note: By default, maprcli stream replica autosetup sets up asynchronous replication. If you want to set up synchronous replication or use any of the other optional parameters, see stream replica autosetup.
To check the replication status, run stream replica list.