In the 3rd part of my series I am going to talk about the usage of vCenter enhanced linked mode and vSphere Replication 6.0 and how it can be used to protect the vSphere replication infrastructure itself.
- vSphere Replication 6.0 –Part 1: Architecture & features at a glance – vSphere Replication standalone and sample network design
- vSphere Replication 6.0 – Part 2: vSphere Replication performance and SLAs
- vSphere Replication 6.0 – Part 3: Architecture & features at a glance vSphere Replication and vCenter enhanced linked mode
In the newest version vSphere replication makes use of the LookupService provided by SSO on the new Plattform Service Controller (PSC). Having multiple vCenter instances sharing the same PSC, the so called vCenter enhanced linked mode, we are not just able to manage all vCenter within a single vSphere Web Client. We can also use vSphere replication to replicate and therefore protect VMs from one site to another and migrate simply a VM back after a restore of the protected site within an integrated view.
The following demonstrated a logical view on a recommended vCenter enhanced linked mode setup.
This architecture has a lot of benefits. You have a vCenter in both sites which is required when you are forced to recover your VMs (in a supported way). As soon as we are having our vCenter in an enhanced linked mode we are able to select all joined vCenter as a target for our vSphere replication protection.
I see very often that the backup strategy of some organizations does not take it into consideration that you very often MUST have a vCenter to recover a VM with your backup solution ( if there is no ’emergency-direct-to-ESXi-recovery-feature’ included). For sure there are ways to register the replicated VM back to on the recovery site, but hey … (officially) we need to make sure that our recovery procedures are supported by the vendor.
In the current situation there is one thing I am uncomfortable with. The current recommended way by VMware tells us to create a dedicated PSC-Cluster with a Network Load Balancer in front of it. Since only NSX, F5 and NetScaler is supported this puts a little additional fee for licensing, operating and implementing of the solution. To be honest, I don’t believe to see such a setup pretty often in non-enterprise environments (On this level people are waiting for vVol replication support ;-)).
The only ‘easier’ suitable option would be to a solution like the following in place
Referring to VMware blog post on the new PSC architecture possibilities the only recommended option is the one mentioned in the beginning. I am currently evaluating and searching discussions about the pros/cons of the mentioned configuration. I will write about the findings in a different post.
Protect and Recover vSphere Replication Appliances and Server (Demo)
It’s worth to remember protecting the vSphere Replication Appliances as well, so that in case of an outage your are able to bring back the replication infrastructure pretty painless. I am going to show you how to recover from a vSphere Replication Appliance data-loss.
In my Lab environment I have two sites and I am going to protect the vSphere replication appliance from LE02 (managed by LE02VCE03) to LE01 (managed by vCSA01). The PSC of each vCenter has joined to the same SSO-Domain.
On my protected site I have 6 machines protected.
In the first scenario I have lost my vSphere replication appliance data on the protection site, so I recover it (vSRA) with help of vSphere replication
and once the original site has been restored, I failback to it via cross vCenter vMotion.
One thing you need to take care of is that the vSphere Replication Appliance and Server are registered against a vCenter. If you restore this machine in the way I described it above or with any other backup solution that restores the VM you need to make sure to re-register the VM with the vCenter, otherwise you see the following error within the vSphere replication menu.
So what to do? Register the recovered VM as a vSphere replication server
and verify that all of your vSphere replication jobs are still in place / running.
Voila… we recovered the vSphere Replication Appliance and can go on with our next test.
Recover protected virtual machines with and failback with cross vCenter vMotion (Demo)
My protected site has been failed and the data has been lost. Lucky me I was able to recover all protected VMs on my recovery site. Depending on the network-characteristics you might be forced to change the IPs of your VMs (PowerCLI can be your friend 😉 )
After the rebuild of my primary site. I was able to to failback/migrate all VMs with cross vCenter vMotion to the original site.
Finalize the steps and voila. You have successfully failed back the VMs.
Make sure to configure a re-protection of the virtual machines.
Final words
The thing I am still missing is a smooth way of having a simple setup of a vCenter in a linked mode. Once I lost my protected site the behaviour of the Web Client was getting really slow and sluggish. Even after the site recovery I needed a reboot of my primary vCenter to get it fully functional again. At this time I am still not sure what’s the best way to establish a vCenter in enhanced linked mode in a ‘stretched’ environment. Any input / discussions / opinions are very appreciated.