Data Replication Modes; Synchronous Replication - Dell PowerVault MD3600f Functional Manual

Dell PowerVault MD3600f/MD3620f Remote Replication Functional Guide
Figure 1: Examples of Replication Relationships

Data Replication Modes

Data replication between the primary virtual disk and the secondary virtual disk is managed by the
MD36X0f storage arrays and is transparent to host machines and applications.
This section describes how data is replicated between arrays participating in Remote Replication and
the actions taken by the MD36X0f controller of the primary virtual disk if a link interruption occurs
between arrays.
The MD36X0f offers three replication modes: Synchronous Replication, Asynchronous Replication,
and Asynchronous with Write Order Consistency Replication. Each of these replication modes is
designed around a specific set of operational requirements and offers features that may be required of
the disaster recovery solution. These replication modes may be dynamically changed from one mode
to another.

Synchronous Replication

Synchronous replication is defined as the completion of both the local primary write and the remote
write before acknowledgement is made to the host server issuing the I/O. This guarantees that the
remote virtual disks are identical to the primary side virtual disks with each and every write and
provides the highest level of data protection. Synchronous Replication Mode flow is shown in Figure 2.
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