How Offline Synchronization Works

Offline synchronization lets you copy data to be replicated to an external device and then from the device to the Replica server. Offline synchronization is an effective method for transferring huge data volumes with low network bandwidth.

Consider these tips when using offline synchronization:

You calculate the daily change rate of the data being protected on the Master and multiply that value that is based on the number of days that are required for the data to reach the Replica server. For example, if your daily change rate is 2 GB and it takes 3 days before the data can be applied to the Replica, assume the spool size on the Replica to be about 6 GB. You can run scenarios in Assessment mode to derive this information.

The spool must have enough space to hold the value you derived in your estimate. If the spool fills, scenarios must be restarted.
You should choose Continue Offline Sync without verification unless you are certain the copy tool you are using to transfer the snapshot to the replica preserves all security attributes. ACL properties must be identical after copy operations for Offline Synchronization to complete properly. Security attribute mismatches can occur if you use normal copy tools with the verify option. Windows Explorer should not be used as it can change security attributes.

Note: You cannot use offline synchronization for scenarios with scheduled replication or scenarios in which the Master is a UNIX/Linux host.

You can perform offline synchronization for all other types of scenarios. The following examples demonstrate how offline synchronization works for these scenarios.