Reducing 503 errors

[Mahmood Naderan <nt_mahmood@xxxxxxxxxxxxxxxxxxxxx>]

Hello

With the following MPM settings

<IfModule mpm_prefork_module>
        ServerLimit           500
        StartServers               5
        MinSpareServers           5
        MaxSpareServers          10
        MaxRequestWorkers         500
        MaxConnectionsPerChild   0
</IfModule>

I would like to know how can I reduce the occurrence of 503 (service unavailable) error? Should I increase ServerLimit only? Or MaxRequestWorkers? Or increasing one and decreasing the other?

Regards,
Mahmood