Very long TTFB (16 seconds) help please

[pmeenan]

Can they make access to mod_status available? - http://httpd.apache.org/docs/2.2/mod/mod_status.html

If so then you can query (or even plot over time) the apache stats and that should give you an idea if you are running out of clients. Running out of available clients will not show up in the server load stats and if they are running their business on hosting websites they should at least be able to monitor the available clients and tell when the server config is out of capacity.