I’d use wrk2 or httperf to recreate a spike that hits an http endpoint. If you don’t see a spike but see one with https then you know ssl is one factor.
It’s also interesting that this happens st around 23000 connections. If you reduce workr count to one or two
And still see max connections around 23000 then it looks another factor is tcp resources.
Sent from my iPhone
> On Mar 19, 2018, at 10:38 AM, Matthew Smith <matthew.smith@acquia.com> wrote:
>
> Hello,
>
> The host has 30G total memory. Nginx usage is being measured by summing the Pss values from /proc/$pid/smaps for all worker processes.
>
> Do you have any suggestions for differentiating between the two issues that might prevent memory from being returned to the system?
>
> Thanks!
>
>> On Thu, Mar 15, 2018 at 1:06 PM Peter Booth <peter_booth@me.com> wrote:
>> Two questions:
>>
>> 1. how are you measuring memory consumption?
>> 2. How much physical memory do you have on your host?
>>
>>
>> Assuming that you are running on Linux, can you use pidstat -r -t -u -v -w -C “nginx”
>> to confirm the process’s memory consumption,
>>
>> and cat /var/meminfo to view a detailed description of how memory is being used onto entire host.
>>
>>
>>
>>> On Mar 14, 2018, at 1:05 PM, Matthew Smith <matthew.smith@acquia.com> wrote:
>>>
>>
>>> Hello,
>>>
>>> I have encountered what I consider to be an interesting behavior. We have Nginx 1.12.1 configured to do SSL termination as well as reverse proxy. Whenever there is a traffic spike (300 req/s > 1000 req/s, 3k active connections > 20k active connections), there is a corresponding spike in Nginx memory consumption. In this case 500M > 8G across 10 worker processes. What is interesting is that Nginx never seems to release this memory after the traffic returns to normal. Is this expected? What is Nginx using this memory for? Is there a configuration that will rotate the workers based on some metric in order to return memory to the system?
>>>
>>> Requests per second:
>>> https://www.dropbox.com/s/cl2yqdxgqk2fn89/Screenshot%202018-03-14%2012.38.10.png?dl=0
>>>
>>> Active connections:
>>> https://www.dropbox.com/s/s3j4oux77op3svo/Screenshot%202018-03-14%2012.44.14.png?dl=0
>>>
>>> Total Nginx memory usage:
>>> https://www.dropbox.com/s/ihp5zxky2mgd2hr/Screenshot%202018-03-14%2012.44.43.png?dl=0
>>>
>>> Thanks,
>>>
>>> Matt
>>
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