I created an debian 9 machine with ISPConfig - standard stuff (after this tut: https://www.howtoforge.com/tutorial/perfect-server-debian-9-stretch-apache-bind-dovecot-ispconfig-3-1/ ). Comes with PHP 7 out of the box... I added PHP 5.6 (after this: https://www.howtoforge.com/tutorial/how-to-install-php-7-on-debian/ ) and in general it works. But when trying to connect to a mysql (Maria) db the error log shows:
[Fri Jan 04 22:05:13.725538 2019] [proxy_fcgi:error] [pid 3617] [client xx.xx.xx.5:61335] AH01071: Got error 'PHP message: PHP Warning: mysqli_real_connect(): (HY000/2002): No such file or directory in /var/www/clients/client1/web2/web/lib/adodb/drivers/adodb-mysqli.inc.php on line 109\n', referer: http://gallery2.my-website.de/install/index.php?step=5
I tried to run PHP 5.6 as fast-cgi or php-fpm - same result. Switching to PHP 7 then it works - same adodb driver file as shown in the log! So I guess it has something to do with missing stuff within PHP 5.6.
And ideas where to look?!