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Creating a high availability solution for Oracle databases often involves creating a copy of the data on another storage device and synchronizing that data in some manner. Dell Unity replication provides data synchronization between Dell Unity systems. Data is replicated at the consistency group or at the LUN and file system providing a choice of replication settings on a per-volume basis. Using Dell Unity replication can be an effective way to protect Oracle databases due to the flexibility and configuration options that it provides. The variety of options provide a robust way to develop a replication scheme that provides the proper mix of performance and bandwidth efficiency while still meeting RTO and RPO requirements.
When using Dell Unity replication to protect Oracle databases that are on multiple volumes, contain all ASM devices for a database within a consistency group. Then configure replication on the consistency group.
Dell Unity storage supports both asynchronous and synchronous replication. A flash tier is recommended (in a hybrid pool) for both source and destination pools where replication will be active.
Asynchronous replication takes snapshots on the replicated storage objects to create the point-in-time copy, determining the changed data to transfer and maintain consistency during the transfer. Consider the overhead of snapshots when planning performance and capacity requirements for a storage pool that will have replication objects.
Setting smaller RPO values on replication sessions will not make them transfer data more quickly but will result in more snapshot operations. Choosing larger RPOs, or manually synchronizing during non-production hours, may provide more predictable levels of performance. Additional information can be found in the Dell Unity: Replication Technologies and Dell Unity: Configuring Replication documents.
Synchronous replication transfers data to the remote system over the first Fibre Channel port on each SP. When planning to use synchronous replication, it may be appropriate to reduce the number of host connections on this port. When the CNA ports are configured as FC, CNA port 4 is defined as the synchronous replication port. If the CNA ports are configured as 10 GbE, port 0 of the lowest numbered FC I/O module is the replication port. Additional information can be found in the Dell Unity: Replication Technologies and Dell Unity: Configuring Replication documents.