proxy_fcgi:error and 503 errors

[j.kaspar]

Hi everyone, could someone please help me with a strange issue?

 

Everyday, my prestashop (v 1.6.1.13) gets randomly unaccesible. After several minutes, the user usually receives error 503. This state lasts from a few minutes to a half an hour. During that time the FO and BO is "dead". Then suddenly everything returns to normal. It repeats basically a whole day. There are no cron jobs or anything similar I know about, that could possibly make the site busy. The shop is on a webhosting, so my diagnostic options are limited.

 

There are a lot of 503 errors in accesslog, but the entries does not seem to have something in common. The error log contains a few dozens of entries like this:

[Thu Jun 01 12:31:02.736606 2017] [proxy_fcgi:error] [pid 21932:tid 140153211283200] (70007)The timeout specified has expired: [id 6GqmfHsxSQI] [client xxx.xxx.xxx.xxx:7259] AH01075: Error dispatching request to : (polling)

However, these errors does not always correspond with the 503 errors in accesslog, so I cannot say, that these errors are the only cause of the inaccessibility.

 

What could I do to find the cause? I searched for the proxy_fcgi errors, but found nothing related to prestashop or similar in any way.

 

Any help will be greatly appreciated

Edited June 1, 2017 by j.kaspar (see edit history)