What are the benefits for several servicehosts? Does one ServiceHost support several simultaneous connections on one endpoint?

I'm thinking of self-hosting my WCF service instead of using IIS. A big question for me is whether I need to instantiate multiple servicehosts as IIS does or one wil be enough.

Do muptiple servicehosts give any benefit except开发者_Python百科 security reasons dut to isolation?

Can one servicehost serve multiple connections on one endpoint simultaneously?

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There's no benefit or choice, really - one ServiceHost (instance of that class) can host exactly one service, and for each service, you need a separate service host. It's a 1:1 mapping - always, no choice.

But of course, your Windows NT service or console app can have multiple ServiceHost objects active at the same time. This can be useful if you have a set of services that logically belong together and can't really exist without one another - where it doesn't make sense to have one of them started and another one not started.

And yes, a service host can host a service which exposes multiple endpoints, and multiple clients can connect on those separate endpoints at the same time, no problem. The WCF runtime will spin up a number of worker threads to handle incoming requests (you can limit those with the ServiceThrottling behavior) independently of each other.

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To set up and control, how many concurrent calls and requests you have, you'll need to look at the ServiceThrottling behavior on the server side.

<behaviors>
    <serviceBehaviors>
        <behavior name="serviceThrottled">
            <serviceThrottling
                maxConcurrentCalls="16"
                maxConcurrentInstances="26"
                maxConcurrentSessions="10"/>
        </behavior>
    </serviceBehaviors>
</behaviors>

and you need to reference that service behavior configuration in your service declaration, of course:

<service name="YourService" behaviorConfiguration="serviceThrottled">
  .....
</service>

These are the default values. The explanations are as follows (taken from Dan Rigsby's blog post, shortened):

• MaxConcurrentCalls (default = 16) [Per-message] The maximum number of messages that can actively be processed.

• MaxConcurrentInstances (default = 26) The maximum number of InstanceContext objects in a service that can execute at one time. For per-session service, this is equal to the maximum number of sessions, for per-call service, it's the maximum number of concurrent calls, and for singletons, it's pointless.

• MaxConcurrentSessions (default = 10) [Per-channel] The maximum number of sessions that a service can accept at one time. Only comes into play with session-based bindings (wsHttp or netTcp)

Definitely also check out Dan Rigsby's excellent blog post on the topic.