stream replica add

Registers an existing stream as a replica of the specified stream.

NOTE
A license is required to run this command. Running this command without a license can cause the command to hang. See Adding a License.

Permissions Required at the Source Cluster

To run this command, your user ID must have the following permissions:
  • readAce and writeAce on the volume
  • lookupdir on directories in the path
  • adminperm and copyperm permissions on the source stream
NOTE
The mapr user is not treated as a superuser. HPE Ezmeral Data Fabric Streams does not allow the mapr user to run this command unless that user is given the relevant permission or permissions with access-control expressions.

Permissions Required at the Target Cluster

To run this command, your user ID must have the following permissions:

Syntax

CLI 
maprcli stream replica add
	 -path <stream path>
	 -replica <remote stream path> 
	[ -paused <start replication in paused state> default: false ]
	[ -throttle <throttle replication operations under load> default: false ]
	[ -networkencryption <enable on-wire encryption> default: false ]
	[ -synchronous <replicate to remote stream before acknowledging producers> default: false ]
	[ -networkcompression <on-wire compression type: off|lz4|lzf|zlib> default: compression setting on stream ]
REST http[s]://<host>:<port>/rest/stream/replica/add?path=<path>&replica=<name>

Parameters

Parameter Description
path The path and name of the stream that you want to create a replica for.
replica The path and name of the stream that you want to create as a replica of the stream that you specified with the -path parameter.
paused A boolean value that specifies whether to pause the replication so that it does not start immediately. The replication can be resumed using the replica resume command at a later time. The values are true or false. The default is false.

Set -paused to true if you want to run mapr copystream to load the replica stream before starting replication. If it is not paused, replication starts immediately after you run the commands maprcli stream replica add and maprcli stream upstream add, in which case the replica stream starts empty and accumulates messages over time. If you are interested only in the messages that are published to the source stream after replication starts, then you do not need to pause replication initially. However, if you want the full set of messages from the source stream that have not yet been purged or marked for deletion, then pause replication initially.
throttle A boolean value that specifies whether to throttle replication operations. Throttle the replication stream to minimize the impact of the replication process on incoming operations during periods of heavy load. The values are true or false. The default is false.
Throttling has two effects, both of which allow HPE Ezmeral Data Fabric Streams to use more system resources to process new messages:
  • Throttling slows down the rate at which changes to a stream are replicated.
  • Throttling slows down the rate at which messages to be replicated are read from disk.
networkencryption A boolean value that specifies whether or not to enable on-wire encryption. The values are true or false. The default is false. If you set the value to true, the local cluster and any other cluster that is part of the replication process must be enabled for security.
synchronous A boolean value that specifies whether replication is synchronous or asynchronous. The values are true or false. The default is false and specifies asynchronous replication.
networkcompression Specifies the type of compression to use when replicating messages. For more information, see Managing Compression.