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From Paul A Houle <p...@cornell.edu>
Subject Re: httpd-2.x servertype inetd
Date Fri, 05 Aug 2005 12:12:23 GMT
Nick Kew wrote:

>Jan Kratochvil wrote:
>  
>
>
>In what sense low-cost?
>
>Apache's high startup cost is self-reinforcing.  We know it's a
>once-only thing, so we have every module do expensive things at
>startup rather than per-request.  I don't see how inetd would
>affect that.  The only thing you'd save is the spawning of
>children, which you already noted ...
>
>  
>
    Funny enough,  the case where I'd think that partial restarts would 
come in handy would be to be able to change configuration on one virtual 
host on a production system without bringing them all down.

    Practically,  it isn't a big issue:  I've run systems in the 10-50 
virtual host range,  and startup time seems to be a few seconds.  Our 
apache is basically stateless,  so probably one person has to reload and 
a few people see a transient broken image:  no apps screw up.  We add a 
new virtual host or make a config change maybe once or twice a week,  so 
it's not terrible.

    I wonder what mass hosting places with 1000's of hosts do,  but I 
guess they use dynamic methods of implementing vhosts,  batch config 
file changes,  and are a little more tolerant of downtime.

    Contrast this the ColdFusion MX server,  which back ends one Apache 
system I look after.  It runs very well once it's up,  but startup takes 
about 30 seconds.  Internal state kept on the server has two 
consequences:  we have to restart it often when we make configuration 
changes in an app or after an app transitions to a bad state,  also a 
restart breaks sessions,  seriously inconveniencing users.

    I always laugh when people tell me that web apps need to keep state 
in RAM in order to be scalable...


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