@Mark Bailey
The post of
@IgorG points in the direction of a (potential)
work-around, it will probably work though.
However, it is
not a FULL solution to the
root cause of the problem.
It can be safely stated that you have some issue at the (backend) Apache server, which takes a long time to serve one or more requests with a response.
It is pretty safe to assume that your Nginx proxy is not configured to wait that long: Nginx will close the connection before Apache is finished with the request processing.
In summary, you have
a) one or more requests that take a (very) long time to be processed fully by Apache, implying that
1 - the Apache config has to allow for a long period, in which requests can be processed fully
2 - the
web application at the problematic domain is not coded in such a way that requests can be processed
efficiently and fast
b) Nginx as a proxy, implying that you
also have to tweak Nginx config to allow for a long period, in which Nginx waits for (full) request processing by Apache
In essence, the
root cause of the problem is the (problematic)
web application itself:
any tweak of Apache or Nginx is just a work-around.
In conclusion, it is recommended that you (in chronological order of relevance!)
1 - tackle problem a.2: have a look at potential offending code in the web application and improve code, whenever possible,
2 - tackle problem a.1: tweak Apache config (if offending code cannot be found and/or cannot be changed) and it is recommended to use the following values for
max_execution_time: 300
max_input_time: 300
and please note that
- any higher value is not really a good idea: if your web application requires more than 300 seconds (i.e. 5 minutes), then something is horribly wrong,
- the value of 300 seconds (and 600 seconds at most) will nicely "fit into" the default Nginx config, as shipped with Plesk: higher values often require Nginx tweaking,
3 - tackle problem b: tweak Nginx to wait a bit longer for responses by changing
- timeout settings: this will be done automatically when changing max_execution_time settings (see notes below!)
- keepalive settings: Plesk applies by default the Nginx directive
keepalive_timeout 65; and that is sufficient, but you can always increase it
slightly (see notes below!)
and please note that
- the Nginx directives to work with are: proxy_connect_timeout, proxy_send_timeout, proxy_read_timeout, send_timeout and keepalive_timeout
- Plesk default values for proxy_connect_timeout, proxy_send_timeout, proxy_read_timeout and send_timeout are sufficient and set at 600 (seconds)
- Plesk default value for keepalive_timeout is 65 (seconds)
- Plesk values for
max_execution_time (Apache setting) and
proxy_read_timeout (Nginx setting)
are identical at the
domain level (and 600 seconds server-wide)
- Plesk values for
max_execution_time (Apache setting) and
proxy_read_timeout (Nginx setting)
are an override of
server-wide settings
- do not add custom Nginx settings at the domain level for
proxy_send_timeout and
send_timeout: the server-wide setting of 600 (seconds) is sufficient (and any increase of this value beyond 600 seconds
will increase security risks and/or
can cause severe overloads of the Apache server)
- any custom Nginx setting at the domain level for
proxy_connect_timeout can help, but in most cases an increase beyond the value of 600 seconds will only add value in the scenario of debugging the web application: in production, there often is no need to change this value when using Apache + Nginx in a Plesk eco-environment
and
finally note that it is
not recommended to fiddle with Nginx timeout settings at all:
just use default values, whenever possible!
All of the above is just an elaborate way to explain the whole story and to help you figure out what to do next.
Simply stated, just apply the solution proposed by
@IgorG (and Nginx config will be automatically adjusted to some extent), but be
aware of the fact that you have to find and solve the root cause of the problem, being a web application with code that is not able to process requests efficiently and fast.
Hope the above helps a bit.
Regards.............
Facebook
Twitter
