Websites are not available: ERROR: unable to read what child say: Bad file descriptor (9)

Created:

2016-12-12 03:47:22 UTC

Modified:

2017-08-16 14:11:28 UTC

0

Was this article helpful?


Have more questions?

Submit a request

Websites are not available: ERROR: unable to read what child say: Bad file descriptor (9)

Applicable to:

  • Plesk 12.5 for Linux
  • Plesk Onyx for Linux

Symptoms

  1. Websites with PHP 5.6 served by PHP-FPM are not available.
  2. In /var/log/plesk-php56-fpm/error.log, there are a lot of errors like the following:

    [04-Nov-2016 22:19:58] ERROR: unable to read what child say: Bad file descriptor (9)
    [04-Nov-2016 22:27:19] ERROR: unable to read what child say: Bad file descriptor (9)
  3. There is a big number of domains using PHP 5.6 served by PHP-FPM (more than 1000)

  4. Service php-fpm consumes 100% of CPU usage.

Cause

Child processes of plesk-php56-fpm master process constantly reaches its limits due a big number of websites assigned to this PHP handler.

Resolution

Increase max children limit for php-fpm service in accordance with KB #213949365 article. Note that it will affect a server performance if pm.max_children is too big.

Alternatively, a part of websites can be switched to other PHP handlers.

Have more questions? Submit a request
Please sign in to leave a comment.