Exception `Errno::EAGAIN'

James Turnbull james at lovedthanlost.net
Sun Nov 15 19:08:56 EST 2009


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Eric Wong wrote:
> This is expected.  The kernel wakes up all the workers when there's
> _one_ connection and they all race to accept() one client connection.
> One wins and accepts the connection, 3 lose and go back to sleep.  With
> lots of worker processes, this can be a thundering herd problem but
> that's why we encourage Unicorn as a backend server, not as a frontend
> server.

Ah okay - makes sense.

> Do you by any chance do user switching in your application
> or config.ru?

In the application we do.

> Instead, since 0.94.0, I would do this:
> 
> 	after_fork do |server, worker|
> 	  worker.user('user', 'group') if Process.euid == 0
> 	end
> 
> That way only the worker process drops permissions.  The master really
> doesn't do anything interesting.   Of course *I* would just start
> Unicorn as a regular user and forget the complexity of user switching
> entirely...

Okay thanks - will give that a shot.

Regards

James Turnbull

- --
Author of:
* Pro Linux System Administration (http://tinyurl.com/linuxadmin)
* Pulling Strings with Puppet (http://tinyurl.com/pupbook)
* Pro Nagios 2.0 (http://tinyurl.com/pronagios)
* Hardening Linux (http://tinyurl.com/hardeninglinux)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (Darwin)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iQEVAwUBSwCYGCFa/lDkFHAyAQIyPggA5XPzSOYgf4ekdBGoRcs4wp885eC8C/wY
BIjzdxilCEhA8mqBw4Hrjo5sOebglOukACFla7QaDqyk2t1velQEpxj8sR2StNEe
HHTbng/Jq3ryt4BxNucQWdKvdPTI3WJ3I9APqtGxNyh72FpY08uvAlUv02S8b/Aj
mtFqbqi2gu+tkbOoqW1AeJEabjJHd7HyPhf2YlHowBaHG61bzrFRnuhvqN8R6SAq
j3LI1kRpnTYdwKYEy3sLfR0OUSVmUuDkWjRkYt2tR2fAwCKkq2oupmcDUrvaT2Y2
fbQ8YJzoGjwVVvD1On/u6iNiTHZcOReYiHRsAhmtbaS+eHldSukHQw==
=EyRA
-----END PGP SIGNATURE-----


More information about the mongrel-unicorn mailing list