GELI encryption - CPU requirements?

[Dan Naumov]

Hello (World).

I am in the process of building a new system for a home NAS/webserver
use and the hardware is basically this:

Intel Atom 330 (1,6 Ghz, dualcore), a motherboard based on Intel
D945GCLF2, 2 GB RAM.
Silicon Image SIL3124 4xSATA RAID card (intended to be used in JBOD mode)
1 x 1.5 TB Western Digital Caviar Green (will get more as the need arises)

A pic of the system, for the curious:
http://tranquilpc.files.wordpress.com/2009/03/bbs2-pure-and-simple-storage.jpg?w=500&h=360

I have been looking into encrypting most of the system with GELI using
the default 256bit AES, how big of a performance hit should I expect
on this CPU? I know there is no way of giving any exact estimations
without actual measurements on the given set of hardware, but either
way, assuming long sequential reads or writes off a single SATA disk,
what would you expect your CPU usage to be like and whats the actual
read/write performance hit is likely to be? I tried googling for some
"with and without GELI encryption" kind of benchmarks, but
unfortunately couldn't find any.

Thank you.


Dan Naumov