The extension of vSphere Replication into the main vSphere SKU last year with the release of 5.1 must have been one of the most welcome of changes – and I was overwhelmed with people expressing an interest and asking questions about the technology. I hope it will also spur people to have a great interest in the subject of DR Automation generally – VMware Site Recovery Manager remains a product close to my hear for obvious reasons.
If you want more detail than this blogpost provides – VMworld TV recorded Lee Dilworth & Ken Wenneberg’s session at VMworld 2013 recently:
There are couple of key enhancement to VR in the 5.5 release. Critically, VR.55 adds the ability to deploy new appliances to allow for replication between clusters and non-shared storage deployments. With storage DRS Interoperability – which allows for replicated VMs to be storage vMotioned across datastores with no interruption to ongoing replication. That’s something that’s been a pain point for SRM users for sometime, and challenges remain around SvMotion with array-based replication (ABR), but at least VMware are making in roads into the problem with VR. Of course the UI has been substantially improved – but fair the introduction of multiple points in time support allows administrators to recover to a previous snapshots. That’s something that folks have been asking for a while.
The VR ships as zip file containing two VMs – a core VR appliance and a “add-on” VR Appliance increase you need additional VR servers in your environment. These additional VR appliances allow you to configure replication to upto a maximum of 10 other target locations. Of course there’s nothing stopping having vSphere Replication within a site, to allow for the quick recovery of VMs rather than resorting to backup.
Once VR has been imported it should register itself with the vSphere Web Client, and the Manage button will lead you to create your first site definition if you have a multiple vCenter configuration.
Configuring Replication to Another Site:
If you just want to protect a VM within vCenter – by replicating it from one datastore to another, you merely find the VM you want to protect -and select “Configure Replication”
Enabling Replication on a VM:
1. Right-click a VM(s) and select All vSphere Replication Actions, and Configure Replication.
2. In the wizard you can select your own site or another vCenter that you added earlier. If you select your own site, then replication remains within your site.
3. It is possible to have multiple VR appliances – and have vSphere select the VR that will handle the replication – or manually assign it yourself.
4. Next select a destination for the replication
5. Indicate if you want to use the Microsoft Shadow Copy Services to have a quiesced replication that is consistent.
6. Finally, and this is where it get’s interesting – define your recovery settings. It’s in here you can see the “point in time” instances. Enabling this option allows you to control the number of point in time referrences you retain. So if you keep 3 instance for the next 5-days – you end up with 15 undo levels. Of course its entirely possible that you might set an RPO where you wouldn’t take 3 snapshots/cycles per day. So it would be impossible to only replicate once every 12hrs and 4 snapshots per day… Hence the dialog box states clearly “You may need to adjust the RPO to achieve the desired number of instance per day…”. Also notice that the maximum number point in time instances maintained is 24 – and wanted a weeks worth of roll-back you would need to adjust the keep to be within those parameters – so you’d be allowed 3 instances in a 7-day period (3×7=21 don’t you just love my helpful maths!).