Project-level vs. Share-level Replication

The ZFSSA allows administrators to configure remote replication on both the project and share level. Like other properties configurable on the Shares screen, each share can either inherit or override the configuration of its parent project. Inheriting the configuration means not only that the share is replicated on the same schedule to the same target with the same options as its parent project is, but also that the share will be replicated in the same stream using the same project-level snapshots as other shares inheriting the project's configuration. This may be important for applications which require consistency between data stored on multiple shares. Overriding the configuration means that the share will not be replicated with any project-level actions, though it may be replicated with its own share-level actions that will include the project. It is not possible to override part of the project's replication configuration and inherit the rest.

More precisely, the replication configuration of a project and its shares define some number of replication groups, each of which is replicated with a single stream using snapshots taken simultaneously. All groups contain the project itself (which essentially just includes its properties). One project-level group includes all shares inheriting the replication configuration of the parent project. Any share that overrides the project's configuration forms a new group consisting of only the project and the share itself.

For example, suppose we have the following:

• a project home and shares bill, cindi, and dave.

• home has replication configured with some number of actions

• home/bill and home/cindi inherit the project's replication configuration

• home/dave overrides the project's replication configuration, using its own configuration with some number of actions

This configuration defines the following replication groups, each of which is replicated as a single stream per action using snapshots taken simultaneously on the project and shares:

• one project-level group including home, home/bill, and home/cindi.

• one share-level group including home and home/dave.

Due to current limitations, do not mix project- and share-level replications within the same project. This avoids unpredictable results when reversing the replication direction or when replicating clones. For more details, see sections Managing Replication Packages and Replicating Clones .