migration - Which CentOS version for migrated web server?

I recently got a side job migrating a website from shared hosting to a VPS. The site is running on Django + Apache (mod_wsgi) + MySQL. The current host is running CentOS 5.6 (32-bit); should I take advantage of the move to switch to CentOS 6? And given the choice of 32-bit or 64-bit CentOS, should I stick with 32-bit or switch to 64-bit?

(I'm more experienced with development than with sysadmin stuff, hence my question. I also know Debian/Ubuntu much better than CentOS, but I'd like to get familiar with CentOS, and this is a fairly low-complexity setup to get started with.)

Answer

There are several PROs and CONs:

5.x vs 6.x

1. Does your new provider actually support CentOS 6.0 right now? For example, Rackspace Cloud only promises Centos 6.0 support "soon", right now you'll have to start with 5.6.




2. Do you value more recent packages or you need to support legacy software, especially closed-source built for version 5.x? If you don't need to support older software, I'd say start using newer version.





3. Do you know there's no upgrade path from 5.x to 6.x? E.g. you'll have to do a complete re-install if you install 5.x now but need 6.x later.

32-bit vs 64-bit

1. What does your hosting support? Some provide only 64-bit or only 32-bit supported platforms? E.g. some Amazon cloud instances are only 32-bit, and Rackspace cloud instances are 64-bit only.




2. Generally speaking, 64-bit system takes more RAM to do the same job as 32-bit system. However, it can also support and efficiently manage more memory. If you're planning 4GB server or larger, by all means, 64-bit is the way to go. If, on the other hand, you'll have 2GB of memory in your server, you don't really need 64-bit, and 32-bit system will manage your existing memory with less waste.