Theoretical connections/second limit using Varnish
nick at loman.net
Wed Apr 29 18:30:04 CEST 2009
Michael S. Fischer wrote:
> On Apr 29, 2009, at 9:22 AM, Poul-Henning Kamp wrote:
>> In message <49F87DE4.3040300 at loman.net>, Nick Loman writes:
>>> Has Varnish got a solution to this problem which does not involve
>>> time-wait recycling? One thing I've thought of is perhaps SO_REUSEADDR
>>> is used or could be used when Varnish makes connections to the backend?
>> Varnish tries as hard as reasonable to reuse backend connections,
>> so you should be able to get multiple requests per backend connection.
>> If this is not the case for you, you should find out why backend
>> are not reused.
Hi Poul-Henning, Michael,
I've configured Apache with KeepAlive off, so I expect the TCP
connection to be closed after each request and Varnish won't be able to
I've done that for a specific reason relating to backend PHP processes.
Is that what you mean?
I typically have thousands of connections in TIME_WAIT mode as a result,
which is expected, but I wonder what the solution could be if I ever hit
more connections than local ports available.
If I turned Keep Alive on with Apache, could Varnish multiplex different
requests from different TCP sockets to the same backend connection?
> The OP said he turned backend Keep-Alive off. That's his problem.
Right, exactly, but I want it this way assuming that leaving it on means
that each user connection translates to one backend connection to Apache
- not desirable - but perhaps this is not how Varnish operates?
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