On 2011-11-07 21:32, Erik Torlen wrote: > If you get a burst against 3 active backend servers they will take > care of all the request and connections. The clients that are active > will then get a persistence sessions against 1 of these 3 servers. It > will take ~5min to scale up a new server so during that period more > clients could come in and the 3 backend would then be even more > overloaded.
You should take care to not overload your backend servers in the first place. The connection limits can be finely tunes your each backend server. Requests exceeding the limits are queued which will prevent your servers from getting overwhelmed and dieing, usually taking others with it. Generally, I think you should make sure that your service is not getting overwhelmed by starting new instances earlier so you can actually handle the traffic. But in the end, I think it depends on how important session locality is for your service, i.e. which of those you can accept earlier: broken session locality or slightly delayed responsed due to queing. --Holger
