Amazon EC2 - Which Ubuntu server to choose: 32bit or 64bit?

Question

I'm in the process of selecting an AMI for my website on the Amazon EC2 network. It seems like the Ubuntu instances come in either 32 or 64-bit flavours. Presumably, the 64 bit systems give you more memory address space, which is good. However, I'm wondering if it is a problem finding pre-compiled binaries. Am I better off sticking with 32 bit? My web application is not terribly memory intensive.

Why would I select one over the other and what are the pros and cons?

Answer 1

You should make your decision based on the size of the servers you want.

32-bit AMIs only run on m1.small, whereas 64-bit AMIs only run on m1.large and m1.xlarge instances (plus the respective High CPU variants).

Larger instances obviously cost more money, with price theoretically scaling linearly with performance. However, I've found that large and xlarge instances actually have a little more performance/dollar than small instances.

Instead of being due to 32- or 64-bit architecture, this seems to be because of contention on I/O controllers. If you are doing serious work on EC2, I would suggest going with m1.large instances, and also the 64-bit AMIs that that entails.