Nginx upstream zone

[Sergey Kandaurov]

> On 8 Aug 2022, at 06:49, Sergey A. Osokin <osa at freebsd.org.ru> wrote:
> 
> Hi,
> 
> On Fri, Aug 05, 2022 at 07:40:35PM +0530, Vishwas Bm wrote:
>> 
>> What is the use of zone in stream upstream
>> http://nginx.org/en/docs/stream/ngx_stream_upstream_module.html#zone
> 
> Since this is the part of the commercial subscription, I'd recommend
> to contact NGINX Plus premium support team, please visit the following
> page to get details, https://www.nginx.com/support/

And also included in opensource nginx.

> 
>> Does it have any impact on how loadbalancing happens when there are
>> multiple worker process?
> 
> No impact.

Actually, enabling upstream zone moves internal peer state storage
to shared memory, such that loadbalancing becomes consistent among
worker processes.  This includes reusing SSL sessions to backends.

> 
>> Also how is the size needs to be calculated ?
>> Is 5m size sufficient for 10 worker process?
> 
> That depends on the actual NGINX Plus configuration and other factors,
> usually 64k is enough, but that number can be revisited with an extensive
> testing in a lower environments.
> 
> Thank you.
> 

It's roughly 500 bytes per upstream server in a simple case.
The exact numbers depend on nginx version and configuration.
Also, currently upstream zone cannot be configured to be less
than 8 page sizes.

-- 
Sergey Kandaurov