nginx high i/o

[Stefanita Rares Dumitrescu]

actually i got a bunch of errors, in error log, as i enabled it to get 
some idea on what's going on:

2009/11/21 08:47:44 [warn] 24393#0: *57036 an upstream response is 
buffered to a temporary file /var/tmp/nginx/fastcgi_temp/1/56/0024741561 
while reading upstream, client:

i am so sleepy right now, could you please tell me where do i get the 
fastcgi buffers optimizations ? i searched on the wiki but i can't think 
straight.



Maxim Dounin wrote:
> Hello!
> 
> On Sat, Nov 21, 2009 at 12:21:52AM +0100, Stefanita Rares Dumitrescu wrote:
> 
>> hi guys,
>>
>> i have posted a question a while ago, and now i am coming back once more.
>>
>> i have now a dual quad core xeon system, running freebsd 7.2 latest
>> patch level, 64 bit, and 16 gb ram. using the latest nginx-devel.
>>
>> the OS runs on a ssd, the db is set on a normal drive, and the site
>> files reside on another ssd.
>>
>> i had a pretty similar config just instead i was using centos.
>>
>> the i/o on the main drive (os drive) is constantly at 22 mb/s.
>>
>> i have disabled nginx logging, and everything has been setup from
>> the ground. i have no idea why do i get such high i/o, because i
>> have no other apps that could cause this load.
> 
> Do you use proxy for big replies and/or have big client uploads?
> 
> If yes, it's probably caused by disk buffering (you should have 
> warnings in logs, but you have no logs...) and you probably want to 
> tune your buffer sizes and/or proxy_temp_file_max_size.
> 
> Maxim Dounin
> 
>> could you please point me to some direction ? i don't know what to do.
>>
>>              ad4              ad5              ad6
>>   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s
>>  54.56 428 22.79   0.00   0  0.00  32.89   4  0.14
>>  55.05 492 26.46   0.00   0  0.00  26.38   8  0.21
>>  55.24 452 24.40   0.00   0  0.00  36.36   5  0.20
>>  53.20 457 23.76  22.31  19  0.42  19.88   8  0.16
>>  53.33 464 24.15   0.00   0  0.00  48.47  23  1.11
>>  54.14 403 21.32   0.00   0  0.00  16.18 217  3.43
>>  52.75 406 20.90   0.00   0  0.00  17.49 178  3.04
>>  55.75 402 21.90   0.00   0  0.00  13.42  12  0.16
>>
>