Replication Policy¶
The Replication Policy contains a list of Member Nodes that are specifically preferred or blocked as replication targets. The Replication Policy also contains a setting that specifies if replication is allowed or disallowed, and the preferred number of replicas.
The Replication Policy is applied to new objects as they are created. The Replication Policy can also be updated on existing Science Data Objects with setreplication.
The DataONE infrastructure will never replicate an object to a Member Node that is in the list of blocked Member Nodes for that object. If a Member Node is added to the list of blocked Member Nodes after an object has been replicated to that Member Node, the DataONE infrastructure will request that the Member Node in question remove its copy of the object.
If the preferred number of replicas is larger than the number of Member Nodes that have been specified as preferred replication targets, additional Member Nodes that are not in the blocked list will automatically be selected as replication targets.
If the preferred number of replicas is modified on an existing Science Data Object, DataONE will adjust the number of existing replicas by creating and deleting replicas of that object as needed.
Use the get command without any parameters to view the current Replication Policy.
Commands to manipulate the Replication Policy:
clearreplication¶
Clear the replication policy. The cleared replication policy has no preferred or blocked member nodes, disallows replication and sets the preferred number of replicas to zero.
addpreferred <member node>¶
Add Member Node to list of preferred replication targets.
addblocked <member node>¶
Add Member Node to list of blocked replication targets.
remove <member node>¶
Remove Member Node from list of preferred or blocked replication targets.
allowreplication¶
Allow objects to be replicated.
disallowreplication¶
Disallow replication and set the preferred number of replicas to zero.
setreplicas <number of replicas>¶
Set preferred number of replicas. If the preferred number of replicas is set to zero, replication is also disallowed.
