Understanding high availability for VCF as a Service
High availabilityThe ability of IT services to withstand all outages and continue providing processing capability according to some predefined service level. Covered outages include both planned events, such as maintenance and backups, and unplanned events, such as software failures, hardware failures, power failures, and disasters. (HA) is a core discipline in an IT infrastructure to keep your apps up and running, even after a partial or full site failure. The main purpose of high availability is to eliminate potential points of failures in an IT infrastructure.
Responsibilities
For more information about responsibility ownership for using IBM Cloud® products between IBM® and the customer, see Shared responsibilities for using IBM Cloud products.
For more information about your responsibilities when using VMware Cloud Foundation (VCF) as a Service, see Understanding your responsibilities when using VCF as a Service.
What level of availability do I need?
You can achieve high availability on different levels in your IT infrastructure and within different components of your workload. The level of availability that is best for you depends on several factors, such as your business requirements, the service level agreements (SLAs) that you have with your customers, and the resources that you want to expend.
What level of availability does IBM Cloud offer?
Service level objectives (SLOs) describe the design points that the IBM Cloud services are engineered to meet. VCF as a Service is designed to achieve the following availability target.
| Availability target | Target value | Method |
|---|---|---|
| Availability % | 99.9% | Single instance in a single zone. Your workload is restarted on other hosts if a host failure occurs. |
| Availability % | 99.99% | Multiple instances that are distributed across multiple zones or regions. Workload is not automatically restarted across zones or regions, but must be designed and implemented for continuous availability or warm standby between zones or regions. |
The SLO is not a warranty and IBM will not issue credits for failure to meet an objective. Refer to the SLAs for commitments and credits that are issued for failure to meet any committed SLAs. For a summary of all SLOs, see IBM Cloud service level objectives.
A complete business continuity plan also addresses cases such as regional or site failure; and events such as corruption, malware, and user error. Consider the use of replication and backup as part of your planning.
Locations
For more information about service availability within regions and data centers, see Service and infrastructure availability by location.