nginx high memory usage in benchmarks

Martin Reissner mreissner at
Wed Jun 17 22:18:39 MSD 2009

hello igor, i found the culprit. it was the access log. i'm pretty new
to nginx and i just commented the access_log option not knowing that i
had to set it to off to disable it.
as i was monitoring the whole system's ram usage i also got the access
log being written to the filesystem cache. turned it off now and results
look more promising. thanks for answering.


Igor Sysoev wrote:
> On Wed, Jun 17, 2009 at 07:16:16PM +0200, Martin Reissner wrote:
>> hello,
>> i've been running some benchmarks for static content with httperf and
>> autobench to compare nginx to apache's worker mpm. i used the default
>> config on apache (2 worker processes, 150 max clients) and set nginx to
>> use 2 worker processes with epoll and a keepalive_timeout of 15.
>> during the benchmarks i monitored the systems ressources with sar and
>> while i expected nginx to outperform apache in every way possible i
>> noticed that nginx uses way more ram than apache while staying ~1/3rd
>> behind it in cpu usage.
>> the benchmarks request a 10k file repeatedly over multiple persistent
>> connections and while apache used ~5mb throughout the tests nginx took
>> ~70mb. can someone explain to me what the cause of this might be. from
>> what i read its low memory usage is one of the key features of nginx so
>> i'm pretty sure somethings wrong on my side.
> What nginx version have you tested ?
> How many worker_connections did you set ?

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