Rapid Scale-Out with Elastic DRS for VMware Cloud on AWS

The new Rapid Scale-Out policy for VMware Cloud on AWS is ideal for events like disaster recovery and bulk workload migration – enabling you to add up to four hosts in parallel at one time for lightning fast scalability. Rapid Scale-Out is just one option within the Elastic DRS feature in VMware Cloud on AWS.


Elastic DRS (EDRS) is an incredible feature included with VMware Cloud on AWS that I’ve written about previously. Up until now, there have been three different policies to choose from – Storage Only, Performance, and Cost based. With these existing EDRS policies, the scale-out of a cluster only occurs after resource demands remain high for a certain period of time. Once the scale-out is triggered, hosts are added conservatively, in a serial fashion, one at a time. 

Today, I’m happy to announce a fourth policy is now available.


Rapid Scale-Out

EDRS Rapid Scale-Out is configured to react faster and to add hosts in parallel, up to four at a time, to allow a cluster to scale-out more quickly during an event. Some primary use cases that can benefit from this new policy are disaster recovery events, significant VDI power-on events, or even bulk workload migration/power-on events. The Rapid Scale-Out maximum resources thresholds are the same as the EDRS Performance Policy thresholds, but the minimum thresholds are set to 0%. This allows for a scale-out task to kick off quicker but also means we will not automatically scale-in; scale-in will be a manual process driven by the customer.

EDRS Policy CPU Thresholds Memory Thresholds Storage Thresholds
Rapid Scale-Out High: 80%, Low: 0% High: 80%, Low: 0% High: 70%, Low: 0%
Performance High: 90%, Low: 50% High: 80%, Low: 50% High: 70%, Low: 20%
Cost High: 90%, Low: 60% High: 80%, Low: 60% High: 70%, Low: 20%
Storage Only N/A N/A High: 70%, Low: 0%


Enabling the Policy

To enable EDRS Rapid Scale-Out, edit the EDRS settings of your cluster, and choose the new policy.

You can also enable this via the edrs-policy API. Kyle Ruddy wrote a great article on managing EDRS policies via RESTful APIs



For other information related to VMware Cloud on AWS, here are some more learning resources for you:

About the Authors

Jeremiah Megie

Sr. Technical Marketing Architect at VMware

Jeremiah Megie is a Senior Technical Marketing Architect working for VMware. He is responsible for providing education, evangelism, and generating content for VMware Cloud on AWS. Prior to joining VMware, Jeremiah was a Senior Solutions Architect specializing in the design and implementation of vSphere, converged & hyper-converged infrastructure, and disaster recovery with VMware Site Recovery Manager. He has more than 20 years of experience in the IT field where he has held many data center and virtualization based roles ranging from administration and engineering to architecture and leadership; with a background spanning multiple industries including DoD, financial, energy, professional services, and managed services. Jeremiah currently holds numerous certifications including multiple VCPs, VCAPs, and VCIX as well as the VMware vExpert designation. He can be found on Twitter at @vMegie.

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