Technie note: Ethernet vs. USB-2 External Hard Disk

I am enhancing the backup methodology here at BlogBridge Enterprises and was selecting a new 500Gb external hard disk. One choice I made was whether to get an Ethernet , i.e. network attached, hard disk or connect one directly to my Mac via USB-2 or FireWire.

Admittedly being too lazy to do calculations I guessed that the limiting factor on speed of a hard disk would be the hard disk transfer speed itself not the speed of Ethernet-100 vs. USB-2.

Not sure if this is actually correct, but I opted for the convenience of being able to place the hard disk anywhere rather than having yet another contraption attached to my computer.

I had lunch with a bunch of guys who know about OS virtualization and other hard-core systems issues and put the question to them: what would the performance difference be?

Here 's what I learned: one major difference is that the Ethernet connected hard disk has to use the Mac's TCP/IP stack which will eat a lot of CPU. I hadn't thought of that. Excellent point, and proven to be true now that I received and have started playing with my new disk (A LaCie Ethernet Disk Mini.)

Next post will be on my evaluation of Backup software for Mac OS X.