hi,
thanks for a hint. i haven't had any 'clicks' lately, but auth.log from the past shows some signs of ssh attack with exactly the periodicity of the clicking (2-5 seconds per attempt). i'll definitely check this out when it happens again...I had something like this when someone was trying to brute-force my SSH server. Every failure would generate an error in auth.log (and a click from the hard drive.) Took me a while to figure out where the weird noise was coming from.
with best regards, -- Lubos _@_" http://www.lubos.vrbka.net