Bluemix, push application with server.xml vs whole Liberty Server, is there performance difference?

Question

I have a multiple options to push my application to Bluemix, single WAR or EAR file, WAR file with server.xml file if I need some customization in settings or even push whole Websphere Liberty Server. When do I need to use the last option and what its impact on a performance in comparison with other options? Thank you.

Answer 1

In general there is no impact on performance; depending on what you are doing you may result in exactly the same runtime configuration (and thus performance).

The most noticeable difference will come from tuning server.xml: Instead of letting the buildpack choose the runtime configuration (and the "features" that will be running), you can trim down features to a minimum (removing everything you may not be using, including logging for example) or add more capabilities (https, jax-rs, ...).

Pushing an entire server is normally necessary if your customizations just do not fit in just server.xml changes. You may be adding libraries (jar files, e.g. database drivers) that are not part of the buildpack-offered runtime. Again, this may or may not come with a performance cost; it just depend on what changes you are doing.

For for information, see the default server.xml and some possible customizations here. You can also read an example of adding drivers to a buildpack server, MySQL in this case -- this is not specific to Bluemix, but rather a Liberty runtime configuration that you can also apply to Bluemix by pushing a server directory.