cat /opt/pbxware/pw/var/log/mysql/mysqld.err
180321 10:36:05 [ERROR] Error in accept: Too many open files in system
180321 10:45:08 InnoDB: Operating system error number 23 in a file operation.
InnoDB: Error number 23 means 'Too many open files in system'.
1) nano /opt/pbxware/sh/start - check what is the current number of file descriptors: ulimit -n 32768
(CTRL+W limits - location: /opt/pbxware/sh/lib/)
2) cd /opt/pbxware/sh/lib - if default value was changed under this directory there will be a file ulimits.conf
3) nano ulimits.conf - instead of existing value n, set n*2 or n*3 etc.(e.g. if it was set to 16384 you can increase that value to 32768)
4) ps fax - find id od mysqld and asterisk
5) cat /proc/xxxxx/limits - make sure new value is presented (32768)
6) nano /opt/pbxware/sh/start - set ulimit -n 32768
7) /opt/pbxware/sh/stop
8) /opt/pbxware/sh/start