The replication implementation has changed significantly between the 2009.Q3 and 2010.Q1 releases. It remains highly recommended to suspend replication to and from an ZFSSA before initiating an upgrade from 2009.Q3 or earlier. This is mandatory in clusters using rolling upgrade.
There are three important user-visible changes related to upgrade to 2010.Q1 or later:
The network protocol used for replication has been enhanced. 2009.Q3 systems can replicate to systems running any release (including 2010.Q1 and later), while systems running 2010.Q1 or later can only replicate to other systems running 2010.Q1 or later. In practice, this means that replication targets must be upgraded before or at the same time as their replication sources to avoid failures resulting from incompatible protocol versions.
Replication action configuration is now stored in the storage pool itself rather than on the head system. As a result, after upgrading from 2009.Q3 or earlier to 2010.Q1, administrators must apply the deferred updates to migrate their replication configuration.
* Until these updates are applied, incoming replication updates for existing replicas will fail, and replication updates will not be sent for actions configured under 2009.Q3 or earlier. Additionally, space will be used in the storage pool for unmigrated replicas that are not manageable from the BUI or CLI.
* Once these updates are applied, as with all deferred updates, rolling back the system software will have undefined results. It should be expected that under the older release, replicated data will be inaccessible, all replication actions will be unconfigured, and incoming replication updates will be full updates.
Replication authorizations have been moved from their own scope into the Projects and Shares scope. Any replication authorizations configured on 2009.Q3 or earlier will no longer exist under 2010.Q1. Administrators using fine-grained access control for replication should delegate the new replication authorizations to the appropriate administrators after upgrading.