Building a small 4 node cluster - few quick questions about networking

Question

I'm putting together a small 4 node cluster on which I'm going to be running storm. I have a few questions about the networking side of things. First off all the computers are equipped with gigabit ethernet however the hub that I currently have only goes up to 100 megabits. Should I upgrade my hub? Or will the performance gain be negligible? Second I read on a few sites that a hub is not the best piece of hardware to use that a switch would be better for my purposes. I'm trying to use Storm to have one machine pull data down from the internet and then pass it off to the others for processing. Would a switch or hub be more useful? Thanks for all your help folks.

Answer 1

A Router can allow for serious networking capabilities, it's also oftentimes overkill. With only 4 machines you're probably much more likely to want a Gigabit Switch instead: sold in stores oftentimes under the name Gigabit Router -- which is technically a lie as it's usually a Bridge (Hub or Switch, Networking has a lot of overloaded names). Router are many times more expensive than Switches if you have difficulty identifying between the two from just marketing names. A hub on the other hand is oftentimes a dumb Switch with less capabilities (and sometimes speed penalties in high data flow situations).

The question as to if you need to upgrade is dependent on where you bottleneck is. Is the data you're sending large? Do your cluster computer spend a lot of time computing instead of receiving data? First determine if your networking speed will be your bottleneck, then decide if you should upgrade that bottleneck. If you're worried about network speed but aren't 100% sure it will be a bottleneck, a cheap 1 Gigabit Switch won't cost you much and will almost certainly meet you're needs.

Also note that if you're data needs to first come over the internet (isn't generated on your side of the network) you're bottleneck will almost certainly be your internet connection before your local network.

So essentially, profile your problem before making a choice.