Q:

What is the best way to compare the performance of different servers?

I've got a site with a LAMP stack and I'm looking at moving to a new hosting provider (currently on a dedicated server and looking to move to a cloud provider). What is the best/most reliable way to compare performance of my site on the different providers? Obviously I would spin up an instance and transfer of a copy of my site, but are there any tools or specific things I should be looking at to compare performance?

A:

Anything other than a real workload will not tell you if the new system is faster. It could have slower CPU, less memory, slower disk but still give faster throughput simply because it's closer to your userbase.
fio is handy for comparing disk I/O. 
ab is better than nothing - bt for more realistic testing then have a look at www::mecanize/http::recorder.

