postfix-users March 2011 archive
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postfix-users: Re: Re : Re : Re : Re : Re : slow transport, mast

Re: Re : Re : Re : Re : Re : slow transport, master.cf and maxproc value

From: Victor Duchovni <Victor.Duchovni_at_nospam>
Date: Sun Mar 06 2011 - 22:49:16 GMT
To: postfix-users@postfix.org

On Sun, Mar 06, 2011 at 10:43:54PM +0000, myrdhin bzh wrote:

> > slow unix - - n - 3 smtp -o
> >smtp_connection_cache_on_demand=no -o smtp_destination_concurrency_limit=2
>
> >> The second "-o ..." option is pointless and should be removed.
>
> Ok.
>
> >> Concurrency limits are enforced in the queue manager, individual delivery
> >>agents just deliver one message at a time, it is the queue manager that knows
> >>about multiple deliveries in progress.
>
> So, in my "slow" configuration, the queue manager can only max "create"
> 3 'smtp' delivery agents.

No, the *process* limit of "3" is implemented in master(8), which spawns
processes on demand, up to the process limit. The concurrency limit
(parallel deliveries to a single destination domain) is enforced in the
queue-manager. The queue manager concurrency limit is a maximum, the actual
concurrency will be lower when the master(8) daemon process limit is reached,
or mail arrival is not high enough to reach peak concurrency.

> But each can only deliver one message at a time and i have only
> one domain in my transport table to the 'slow' deliver, so only 2 'smtp'
> delivery agents can be created and deliver concurrency. The 3 in my master.cf
> slow line is useless ?

No, the "-o smtp_destination_concurrency_limit=2" is useless.

-- Viktor.