How it works
Sizes
The create page lists sizes by their specs, for example 0.5 vCPU · 1 GB. For prices, see Raff Apps pricing.
An app cannot use more CPU than its size: a busy app runs slower instead. An app that runs out of memory is stopped and restarted. Change the size in Settings, Instance size; the app restarts on the new size.
Fixed instances
Web, private and worker apps run 1 to 6 instances. Each instance runs all the time and is billed at the size’s price. Set the number in Settings, Scaling, Instances.Autoscaling
Web apps, and private apps that scale to zero, can scale between Min instances and Max instances. Raff adds instances as the number of requests in progress per instance grows, and removes them as traffic drops. Workers and private apps that run all the time use a fixed number of instances.Scale to zero
Web and private apps can sleep. With Scale to zero on, the app sleeps about 15 minutes after its last request and wakes on the next one. The first request after sleeping takes a few seconds longer while an instance starts. On pay-as-you-go, a sleeping app costs nothing; the minutes it is awake are billed like any running time. With autoscaling, scale to zero lets Min instances be 0.Instance limits
Cron and job apps do not count. Scaling down is always allowed, even above a limit. Contact support to raise either limit.
When to use it
- One fixed instance: most small apps, and any app that keeps state in memory.
- Several fixed instances: steady traffic, no waiting for new instances.
- Autoscaling: traffic that rises and falls during the day.
- Scale to zero: test apps, internal tools and sites with little traffic.
Trade-offs
- The first request after sleeping is slower by a few seconds.
- Workers cannot sleep or autoscale.
- Instances do not share memory or disk. Keep shared data in a database.
- On monthly billing, the size cannot be changed from the dashboard yet. Contact support to change it.
Related
Scale an app
Instances, autoscaling and scale to zero.
Pricing
The price of every size.