什么是php-fpm警告“未能获得记分牌”？

Question

what is php-fpm warning "failed to acquire scoreboard" in fpm error log?

tail -f /var/log/php-fpm.log
[08-Oct-2014 03:36:36] WARNING: failed to acquire scoreboard
[08-Oct-2014 03:40:39] WARNING: failed to acquire scoreboard
[08-Oct-2014 03:42:54] WARNING: failed to acquire scoreboard
[08-Oct-2014 03:47:01] WARNING: failed to acquire scoreboard

use-case:

php version 5.4.25

php-fpm instance say 'pf-9000' is connecting to 2nd php-fpm instance say 'pf-9005' with fastcgi protocol on same server. The error is visible on both php-fpm instances.

Request flow:

web client -> nginx -> pf-9000 -> pf-9005

Response flow:

pf-9005 -> pf-9000 -> nginx -> web client

Answer 1

A scoreboard is a structure that holds the state of the FPM pool and its worker threads. It's created in shared memory, and if that memory can't be allocated, an error is logged.