Does sending restarts have performance implications

[Maccaday]

Hi,

I'm planning an API for a potentially high-use Apache installation (as a multi-site server), and was wondering whether sending graceful restarts had a significant effect on performance.

I am going to be setting it up so that clients can (through an API) change certain parts of their virtual host container settings in the httpd.conf file, as well as adding new virtual hosts possibly quite regularly. Obviously these updates will only come into effect once the server is restarted, and I was wondering if I allowed clients to launch a graceful restart, whether it would affect the server as a whole or not.

I would probably place a lower bound on the time between restarts (such as 10 secs or 30 secs) anyway, but if it was to affect server performance, then I might only allow one per hour say.

Anyone with any comments?

Cheers.

 

[siberian]

Any restart has a performance impact since you have to spawn a new child, re-read configs etc. That said, its minor for the most part but a lot depends on your applications and load.

One site we have gets millions and millions of hits a day but since its load balanced on 4 servers we can graceful restart each one and any load is absorbed into the rest of the cluster.