Oracle ZFS Storage Appliance Replication is a licensed feature for certain models that provides snapshot-based replication of projects and shares from a source appliance to one or more replication targets. Replication performs a full update of an entire project and/or share contents, followed by incremental updates containing only the changes since the previous update.
For license details, refer to the "Oracle Software License Agreement ("SLA") and Entitlement for Hardware Systems with Integrated Software Options" and the Licensing Information User Manual for the software release.
This topic describes key remote replication (or simply "replication") concepts and replication terminology.
Remote replication has the following important characteristics:
Snapshot-based asynchronous replication - The replication subsystem takes a snapshot as part of each update operation. In the case of an initial update, the entire contents of a project and/or share are sent. In the case of an incremental update, only the changes since the last replication snapshot for the same action are sent. Because replication takes snapshots and then sends them, data is already committed to stable storage before replication even begins sending it. Continuous replication effectively sends continuous streams of filesystem changes, but it is still asynchronous with respect to NAS and SAN clients.
Block-level - Each update operation traverses the filesystem at the block level and sends the appropriate filesystem data and metadata to the target.
Includes all metadata - The underlying replication stream serializes both user data and metadata, including most properties configured on the Shares screen. These properties can be modified on the target after the first replication update completes, though not all take effect until the replication connection is severed. For example, this allows sharing over NFS to a different set of hosts than on the source. For more information, see Replication Packages.
Secure - The replication control protocol used among Oracle ZFS Storage Appliance products is secured with Secure Sockets Layer (SSL). Data can optionally be protected with SSL as well. The appliance can only replicate to or from another appliance after an initial manual authentication process. For more information, see Replication Targets.
Encrypted projects and shares - When enabled, transparent data encryption protects individual shares (filesystems and LUNs) and projects. For more information, see Data Encryption.
Protocol independent - The appliance supports both file and block-based storage volumes. The replication mechanism is protocol independent.
Compressed replication - Support for compressed replication streams increases replication performance and improves throughput utilization between multiple sites that have limited bandwidth connections. For more information, see Compressed Replication.
Replication has the following known limitations:
Actions cannot move between pools
Network throughput is limited to a maximum of 200 MB/s per project level replication. With compressed replication, the effective data rate can exceed the actual physical network data rate.
For information about remote replication concepts, see: