High availability can be achieved for physical infrastructure, virtual infrastructure, and application services. High availability is measured by uptime, the amount of time that a service has been operational.
Designing for High Availability
The VMware Cloud Providers typically have multiple physical data centers in various regions throughout the world. The data centers in each region are designed to be independent of one another so that a failure in one data center would not affect another. An organization can choose to deploy their VMware Cloud SDDC in one or more supported regions. The data centers in each region are designed to be independent of one another so that a failure in one data center would not affect another. The VMware Cloud Provider is responsible for providing high availability for the physical infrastructure according to the Service Level Agreements (SLAs).
A VMware Cloud SDDC inherently provides high availability for the Virtual Machines running in the SDDC using vSphere High Availability (HA) and vSAN storage policies. When an ESXi host fails, vSphere HA automatically restarts the Virtual Machines from the failed ESXi host to other ESXi hosts within the same vSphere cluster. vSAN storage policies provide data redundancy through appropriate RAID configurations depending on the number of ESXi host failures an organization can tolerate.
Although a VMware Cloud SDDC provides native high availability capabilities, designing a virtual infrastructure that meets the applications SLAs is ultimately the responsibility of an organization.
An organization can deploy multiple independent VMware Cloud SDDCs, each in a different region where the VMware Cloud Infrastructure Services provider is available. Workloads can be deployed across these environments to satisfy availability requirements. With this method, it is vital to understand the application dependencies and network utilization to design an appropriate network connectivity between the different VMware Cloud SDDCs.
When deploying VMware Stretched Clusters, VMware Cloud SDDCs can span across multiple geographical regions. A VMware Stretched Cluster can achieve higher levels of availability. An additional benefit of deploying a VMware Stretched Cluster is the ability to provide an extra level of local site protection for Virtual Machines by distributing the placement of Virtual Machines across regions. Deploying a VMware Stretched Cluster will incur additional cost due to cross-regional replication traffic.