[VMC on AWS] Failure tolerance in case of stretched cluster and RAID-1 storage policy

Products

• VMware Cloud on AWS

Issue/Introduction

Describe how to configure Storage Policies for true AZ and Host resiliency in a Stretched/MutliAZ Cluster.

Resolution

There are two settings that go into defining a Storage Policy for a stretched cluster in VMC on AWS which are: 

• Site Disaster Tolerance(SDT) which controls Availability Zone resiliency.
• Failures to Tolerate(FTT) which controls resiliency within each Availability Zone.

To be tolerant from an AZ failure the policy needs to be set to : 

• SDT : Dual Site Mirroring
• FTT: 1 Failure Raid-1 or Raid-5.

Note : If SDT is set to anything other then Dual Site Mirroring the data is in one AZ or the other.

Additional Information

https://docs.vmware.com/en/VMware-Cloud-on-AWS/services/com.vmware.vsphere.vmc-aws-manage-data-center-vms.doc/GUID-EDBB551B-51B0-421B-9C44-6ECB66ED660B.html