Feature Brief: Elastic vSAN
Amazons Elastic Block Store (EBS) is a unique capability within Amazon, which presents a pool of durable cloud storage as a local block device. EBS storage is allocated and connected to an EC2 Instance programmatically. This platform provided the perfect building block to construct a new class of vSAN Storage. Using a diskless host type Elastic vSAN enables customers to specify at cluster creation how much storage they require on a per-host basis. The VMware Cloud on AWS Service will then dynamically build the hosts from the component services inside AWS. This flexibility empowers customers to control costs by deploying fewer total hosts where the capacity requirements outstep the compute and memory needs.
The auto-remediation services inside VMware Cloud on AWS have been optimized to minimize resync traffic by taking advantage of the enhanced availability of the EBS media. When a problem is encountered a replacement host is added into the cluster. However, instead of moving the data between the host we instead move the EBS volumes themselves. The new host is reattached the previous EBS volumes thus “moving” all the disk groups and data contained therein.
When a cluster begins to fill up, customers can add capacity by adding additional hosts to the cluster. Or they can choose to add storage to the existing hosts (up to the maximum per host). This change is processed on every host in the cluster and is available on the VMware Cloud on AWS SDDC Console and service API.
Dynamic Scale-Up empowers a customer to start small and incrementally scale-up storage capacity on demand. Thereby controlling costs by right-sizing the SDDC to the needs of the workload. Once the per-host capacity is maxed out, further capacity increases require adding one or more hosts.
Scaling down is still based on host removal. Elastic DRS still uses host addition/removal to right-size the cluster based on utilization.