NetApp HCI, Manual

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Synchronous and asynchronous replication between clusters
For clusters running NetApp Element software, real-time replication enables the quick creation of remote
copies of volume data.
You can pair a storage cluster with up to four other storage clusters. You can replicate volume data
synchronously or asynchronously from either cluster in a cluster pair for failover and failback scenarios.
Synchronous replication
Synchronous replication continuously replicates data from the source cluster to the target cluster and is
affected by latency, packet loss, jitter, and bandwidth.
Synchronous replication is appropriate for the following situations:
• Replication of several systems over a short distance
• A disaster recovery site that is geographically local to the source
• Time-sensitive applications and the protection of databases
• Business continuity applications that require the secondary site to act as the primary site when the primary
site is down
Asynchronous replication
Asynchronous replication continuously replicates data from a source cluster to a target cluster without waiting
for the acknowledgments from the target cluster. During asynchronous replication, writes are acknowledged to
the client (application) after they are committed on the source cluster.
Asynchronous replication is appropriate for the following situations:
• The disaster recovery site is far from the source and the application does not tolerate latencies induced by
the network.
• There are bandwidth limitations on the network connecting the source and target clusters.
Snapshot-only replication
Snapshot-only data protection replicates changed data at specific points of time to a remote cluster. Only those
snapshots that are created on the source cluster are replicated. Active writes from the source volume are not.
You can set the frequency of the snapshot replications.
Snapshot replication does not affect asynchronous or synchronous replication.
Replication between Element and ONTAP clusters using SnapMirror
With NetApp SnapMirror technology, you can replicate snapshots that were taken using NetApp Element
software to ONTAP for disaster recovery purposes. In a SnapMirror relationship, Element is one endpoint and
ONTAP is the other.
SnapMirror is a NetApp Snapshot™ replication technology that facilitates disaster recovery, designed for
failover from primary storage to secondary storage at a geographically remote site. SnapMirror technology
creates a replica, or mirror, of the working data in secondary storage from which you can continue to serve
data if an outage occurs at the primary site. Data is mirrored at the volume level.
The relationship between the source volume in primary storage and the destination volume in secondary