Vsphere Replication appliance bandwidth usage

[lasanthaj]

Dear All,

Our vmware infrastructure include two datacenters . one datacenter locate in our headoffice (primary) and other datacenter (DR)locate at 20km away from our primary datacenter. we added both datacenters to same Vcenter instance and install and configure vsphere replication appliance on primary datacenter. we configure replication two VMs between two datastores on DR datacenter.after initiate replication 10mbps bandwidth constantly consume between vsphere replication appliance and DR site .anyone can expalain following points ?

                      1. Replication appliance receive CBT from DR site VM and resend to DR Site ?

                      2. How to avoid this bandwidth consumption without stopping replication ?

   Really appreciate your ideas.

   Thanks & Regards,

   Lasantha.

[Ivan Angelov]

Can you please check replication states? Initial sync can generate such traffic.

Bandwidth consumption can be optimized with RPO change to find best one.

[lasanthaj]

thanks for quick reply. initial sync finish. current state is " OK ". Vsphere replication appliance collect change block tracking from DR site and resend to DR site ? we can't place replication appliance DR site . because one vcenter instance can only include one vsphere replication appliance.

[mvalkanov]

Hi,

Beware that if using a single vCenter Server for the two sites, you need to have it up and running, in order to perform failover of a replicated VM.

The suggested topology in vSphere Replication documentation is for multiple remote sites replicating to a single DR site and vCenter Server and VR appliance running in that master site. Should the vCenter Server fail, VR can not be used to assemble consistent VM image from the replicated files.

About replication traffic traveling between the sites and back - the replication traffic goes from the source ESXi to the VR server and then to ESXi that has access to the target datastore.

If using SRM 5.0.x or 5.1.x with vSphere Replication, you can install multiple additional VR servers and that way the replication traffic does not need to travel between the sites and back.

In the upcoming 5.5 release, even without SRM, in the Web Client UI, you can install multiple additional VR servers.

After the initial full-sync completes, the bandwidth consumption is proportional to the changed data blocks at the source VM. If in a given RPO interval the same disk block is changed multiple times, it will be transferred only once. As commented above, you might need to adjust the RPO value.

Regards,

Martin