Asynchronous Replication - Dell PowerVault MD3600f Functional Manual

Dell PowerVault MD3600f/MD3620f Remote Replication Functional Guide

Asynchronous Replication

Asynchronous replication removes the restriction that the remote write has to complete along with
the local primary write. The MD36X0f will separately queue each remote write to allow the local
primary write completion to signal Host I/O completion (thus no waiting for the remote write to
complete). Instead, the MD36X0f will manage the queue of remote writes and ensure they all
complete eventually.
Figure 3: Asynchronous Replication Mode
1 Host sends Write Request
2.1 Primary(local) controller at the local site takes in the request and stores the request in
the Replication Repository
2.2 Primary (local) controller writes the data into the primary virtual disk
Primary controller sends the completion status to Host
3
4 Primary controller then sends the write request to the Secondary controller at the
Remote Site
5 The secondary controller then processes the write request
6 Once the write request is processed, Secondary Controller sends acknowledgement
to Primary Controller
7 Primary controller removes the entry from the Remote Repository
Page 7