Reference Guide

Figure 7. Cluster networks

Volumes

Replication-enabled volumes can be created using a combination of PowerShell and Failover Cluster Manager or by using

Windows Admin Center.

NOTE:

Install Storage Replica Module for Windows PowerShell (RSAT-Storage-Replica) on the management node with

Desktop Experience that is used for installing Windows Admin Center and Failover Cluster Manager to access the cluster.

For each replica-enabled volume, you need a corresponding log volume on both sites (with a minimum of 8 GB in size) and an

equivalent replica volume on the secondary site. The log volume is used to serialize writes for replication.

The following table shows the volumes that are needed to create a 1 TB replica volume:

Table 6. Volumes in a 1 TB replica volume

Site A Size Site B Size

VolumeA 1 TB VolumeA-Replica 1 TB

VolumeA-Log 40 GB VolumeA-Replica-Log 40 GB

VolumeB 500 GB VolumeB-Replica 500 GB

VolumeB-Log 40 GB VolumeB-Replica-Log 40 GB

See Appendix A for the correct PowerShell Cmdlets and Failover Cluster Manager steps to create the volumes shown in this

table. It is recommended that you create two-way mirrors for all volumes to improve write performance and capacity efficiency.

NOTE: For Asynchronous Replication, the RPO can be set as low as 30 seconds.

For a planned site failure, when the volume replication direction is reversed, the disk reservations on the secondary site for

Replica Volume and Replica-log volumes are removed and moved to the primary site. Source Data and Source Log volumes are

given the disk reservations and become active on the secondary site. After 10 minutes, the virtual machines residing on the

primary site associated with the migrated volume automatically Live Migrate to the secondary site.

Creating a stretched cluster