Health check frequency
Fastly performs health checks on your origin server based on the Check Frequency setting you select in the New Health Check window. The Check Frequency setting you select will specify approximately how many requests per minute Fastly POPs are checked to see if they pass. There is roughly one health check per Fastly POP per period. Any checks that pass will be reported as "healthy."
To determine origin health, you can configure health checks with the following frequency options:
- Low - Approximately 30 requests/minute, where "healthy" means 1 out of 2 must pass
- Normal - Approximately 120 requests/minute, where "healthy" means 3 out of 5 must pass
- High - Approximately 900 requests/minute, where "healthy" means 7 out of 10 must pass
- Custom - A custom frequency and request health pass levels
To set a custom frequency, select Custom; the following controls appear:
- Threshold & Window - The number of successes per total number health checks. For example, specifying
1/2means 1 out of 2 checks must pass to be reported as healthy.
- Initial - The number of requests to assume as passing on deploy.
- Interval & Timeout (ms) - Interval represents the period of time for the requests to run. Timeout represents the wait time until request is considered failed. Both times are specified in milliseconds.