502 Bad Gateway / Raspberry Pi 2

[nbrucy]

On Raspberry Pi 2, and while synchronising big folder, the owncloud web interface go unreachable with the following error

502 Bad Gateway 

The following is a extract from /var/log/php5-fpm.log :

[29-Dec-2015 13:23:15] WARNING: [pool owncloud] child 25748, script '/var/www/owncloud//index.php' (request: "GET /owncloud/index.php") executing too slow (5.405414 sec), logging
[29-Dec-2015 13:23:15] NOTICE: child 25748 stopped for tracing
[29-Dec-2015 13:23:15] NOTICE: about to trace 25748
[29-Dec-2015 13:23:15] ERROR: failed to ptrace(PEEKDATA) pid 25748: Input/output error (5)
[29-Dec-2015 13:23:15] NOTICE: finished trace of 25748

It seems that I face the problem described here. A solution is to modify /etc/php5/fpm/pool.d/owncloud.conf by commenting the lines :

slowlog = /var/log/nginx/NAMETOCHANGE.slow.log
request_slowlog_timeout = 5

or increasing the value of request_slowlog_timeout

(but it doesn’t seem to work for me, I still get Gateway errors ...)