How big should be timeout for checking via HTTP if site is up?

Question

I'm working on uptime monitoring service and I naively thought that 10 seconds should be enough for checking if the site is up.I check if site is up via 5 nodes, and each node makes 3 tries of HTTP requests with 10 secs timeout.So, 5 nodes. 3 tries. 10 seconds timeout.But I've just found out that it's way too small. So I'm going to change the timeout to 30 seconds.But maybe I'm wrong again, so what would you recommend as a proper timeout?HTTP requests are done with curl.

aww_dang · Accepted Answer

User configurable would be best. 10 seconds seems excessive for most sites. If their app requires a longer timeout, I doubt they are in the majority. Even so, 10 seconds to complete a request would indicate a problem that I would want to be made aware of.