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Overview

Contributors jfsinmsp
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SnapMirror active sync allows you to build ultra high availability Oracle database environments where LUNs are available from two different storage clusters.

With SnapMirror active sync, there is no "primary" and "secondary" copy of the data. Each cluster can serve read IO from its local copy of the data, and each cluster will replicate a write to its partner. The result is symmetric IO behavior.

Among other options, this allows you to run Oracle RAC as an extended cluster with operational instances on both sites. Alternatively, you could build RPO=0 active-passive database clusters where single instance databases can be moved across sites during a site outage, and this process can be automated through products like Pacemaker or VMware HA. The foundation for all of these options is synchronous replication managed by SnapMirror active sync.

Synchronous replication

In normal operation, SnapMirror active sync provides RPO=0 synchronous replica at all times, with one exception. If data cannot be replicated, ONTAP will release the requirement to replicate data and resume serving IO on one site while the LUNs on the other site are taken offline.

Storage hardware

Unlike other storage disaster recovery solutions, SnapMirror active sync offers asymmetric platform flexibility. The hardware at each site does not need to be identical. This capability allows you to right-size the hardware used to support SnapMirror active sync. The remote storage system can be identical to the primary site if it needs to support a full production workload, but if a disaster results in reduced I/O, than a smaller system at the remote site might be more cost-effective.

ONTAP mediator

The ONTAP Mediator is a software application that is downloaded from NetApp support, and is typically deployed on a small virtual machine. The ONTAP Mediator is not a tiebreaker when used with SnapMirror active sync. It is an alternate communication channel for the two clusters that participate in SnapMirror active sync replication. Automated operations are driven by ONTAP based on the responses received from the partner via direct connections and via the mediator.