You can increase or decrease the capacity, performance, and availability of HCP for cloud scale by adding or removing the following:
- Instances: physical computer nodes or virtual machines
- Service instances: copies of services running on additional instances
- Storage components: S3 compatible systems used to store object data
In a multi-instance site, you might add instances to improve system performance or if you are running out of storage space on one or more instances. You might remove instances if you are retiring hardware, if an instance is down and cannot be recovered, or if you decide to run fewer instances.
When you add an instance, you can also scale floating services (such as the S3 Gateway) to the new instance. When you scale a floating service, HCP for cloud scale automatically rebalances itself.
In a multi-instance site, you can manually change where a service instance runs:
- You can configure it to run on additional instances. For example, you can increase the number of S3 Gateway service instances to improve throughput of S3 API transactions.
- You can configure it run on fewer instances. For example, you can free computational resources on an instance to run other services.
- You can configure it to run on different instances. For example, you can move the service instances off a hardware instance to retire the hardware.
- For a floating service, instead of specifying a specific instance on which it runs, you can specify a pool of eligible instances, any of which can run the service.
Some services have a fixed number of instances and therefore cannot be scaled:
- Metadata Coordination
You might add storage components to a site under these circumstances:
- The existing storage components are running out of available capacity
- The existing storage components do not provide the performance you need
- The existing storage components do not provide the functionality you need