Advice please - do I need a vSphere Replication Server?

[JMckechnie]

Hi,

I have been reviewing our current vSphere replication setup. Currently this looks like.

• vSphere 5.5
• 1 x vCentre server
• 1 x vSphere replication appliance
• 2 sites - Local and remote connected over a 10mb WAN link.
• Currently around 50 VMs are replicated from the local site to the remote site only.

This is all working, however i have been reviewing the VMware documentation on this product and am not clear on whether I should use deploy a vSphere Replication Server at the remote site?

Are there any benefits to doing this? Resilience or performance for example? 

https://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.vsphere.replication_admin.doc/GUID-DF5B80D3-...

Thanks

John

[admin]

You aren't in any danger of reaching the limit anyway which is 100 VMs per VR server.

As to possible benefits - replication traffic flows from the ESXi host on the production site to the Replication Server (embedded or external) on the remote site. So it will all be going to a specific ESXi host if you only use the embedded VR server. If you use a one or more external VR servers then you can load balance, so there could be a potential performance benefit.

As far as I know there isn't really any resiliency benefit - if one VR server failed you would have to manually reconfigure the replication to point at another VR server.

[JMckechnie]

Thanks for your response that is very useful.

We are using the VR appliance, which I presume means an embedded version of the replication server? The appliance is located at the 'local' site along with the vCentre server, from looking at the diagrams included in the documentation and even the getting started page, it suggests the appliance or server should be located at the remote site, would you agree with that?

vSphere 5.5 Documentation Center

[vbrowncoat]

Hopefully this excerpt from the VR FAQ Storage and Availability Technical Documents will help:

• vSphere Replication Management Server: Virtual appliance containing both the management component for vSphere Replication and the component that receives replicated data (vSphere Replication Server)
• vSphere Replication Server: Virtual appliance containing the component that receives replicated data but does not contain the management component

The VRMS is the first VR appliance deployed to a vCenter. All subsequent ones are VRS. Same OVF, slightly different functionality.

You (and the documentation) are correct, if you are replicating from the local site to the remote site, it would be better to have the VR server (either VRMS or VRS, whichever the replications are configured with, in your case the VRMS is likely sufficient) located at the remote/recovery/target site. This is because the traffic flow is from the host where the source VM is located to the VR server then to the datastore.