In this episode of “Things My Customers Have Asked Me” (or TMCHAM for short), I’m going to dive into a few questions around VMware Cloud Disaster Recovery (VCDR), a service we offer as an add-on to VMware Cloud on AWS. If you’re unfamiliar with VCDR, you can read a bit more about it here.
VCDR Roles and Permissions
Can RBAC roles be customised? Not really, as these are cascaded down from the Cloud Services hub. As I understand it, I don’t believe you have granular control over it, just the pre-defined, default roles as outlined here, so you need to be careful about what you hand out to folks in your organisation. To see what Service Roles have been assigned to your account, in the VMware Cloud Services, go to My Account, and then click on My Roles. Under Service Roles, you’ll see a list of services, such as VCDR, Skyline, and so on. You can then check what roles have been assigned.
VCDR Protection Groups
VCDR Protection Groups are the way that we logically group together workloads to be protected with the same RPO, schedule, and retention. There are two types of protection group: standard-frequency and high-frequency. Standard-frequency snapshots can be run as often as every 4 hours, while high-frequency snapshots can go as often as every 30 minutes. You can read more on protection groups here. It’s important to note that there are some caveats to be aware of with high-frequency snapshots. These are outlined here.
30-minute RPOs were introduced in late 2021, but there are some caveats that you need to be aware of. Some of these are straightforward, such as the minimum software levels for on-premises protection. But you also need to be mindful that VMs with existing vSphere snapshots will not be included, and, more importantly, high-frequency snapshots can’t be quiesced.
Can you have a VM instance in both a standard- and high-frequency snapshot protection group? Would this allow us to get the best of both worlds – e.g. RPO could be as low as 30 minutes, but with a guaranteed snapshot of 4 hours? Once you do a high-frequency snap on a VM, it keeps using that mechanism thereafter, even if it sits in a protection group using standard protection. Note also that you set a schedule for a protection group, so you can have snapshots running ever 30 mins and kept for a particular period of time (customer selects this). You could also run snapshots at 4 hours and keep those for a period of time too. While you can technically have a VM in multiple groups, what you’re better off doing is configuring a variety of schedules for your protection groups to meet those different RPOs.
Quiesced Snapshots
What happens to a VM during a quiesced state – would we experience micro service outages? The best answer I can give is “it depends”. The process for the standard, quiesced snapshot is similar to the one described here. The VM will be stunned by the process, so depending on what kind of activity is happening on the VM, there may be a micro outage to the service.
Other Considerations
The documentation talks about not changing anything when a scheduled snapshot is being run – how do we manage configuration of the SDDC if jobs are running 24/7? Seems odd that nothing can be changed when a scheduled snapshot is being run? This refers more to the VM that is being snapped. i.e. Don’t change configs or make changes to the environment, as that would impact this VM. It’s not a blanket rule for the whole environment.
Like most things, success with VCDR relies heavily on understanding the outcomes your organisation wants to achieve, and then working backwards from there. It’s also important to understand that this is a great way to do DR, but not necessarily a great way to do standard backup and recovery activities. Hopefully this article helps clarify some of the questions folks have around VCDR, and if it doesn’t, please don’t hesitate to get in contact.