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.

Posted on January 3, 2007 and filed under Technology.