Regarding this Asterisk instance as discussed previously (Asterisk 188.8.131.52)
that was consuming enormous amounts of file descriptors (100 000+ for about
50 simultaneous calls) it appears I have managed to solve my problem by upgrading the 184.108.40.206 Asterisk instance to an 220.127.116.11 Asterisk instance.
Also, the file descriptors apparently leaking were paired with timer problems in 18.104.22.168 whenever I went above about 50 concurrent calls on the box while running on 22.214.171.124.
The thing is in our setup we have about 15 instances of 126.96.36.199 at the various branches of the company, all running 188.8.131.52, BUT at none of these sites do we ever exceed 40 simultaneous calls.
The defining factor was (in our case, with our dialplan) to run 184.108.40.206 and try to run 50+ concurrent calls.
What would happen was that thousands of these messages would come up in the CLI:
[Aug 13 09:41:38] ERROR: res_timing_dahdi.c:89 dahdi_timer_set_rate:
Failed to configure DAHDI timing fd for 0 sample timer ticks
when we reached or exceeded 50 calls.
The same happened whether pthread timing or kernel timerfd timing was used.
Several other weird errors would manifest in the CLI, to whit: