Smoothing disk I/O

["Todd A. Jacobs" <nospam@codegnome.org>]

Is there a mechanism for smoothing disk I/O in a similar fashion using
nice to smooth CPU usage? I often find that certain disk-intensive tasks
put the system into high wait-state load averages, and system
performance as a whole suffers.

Nicing the process doesn't really help, as the system won't release
anything in a wait state. The recent Debian scheduler defaults to CFQ;
is this optimal? What other things can I do to keep the system from
being unresponsive during heavy I/O?

-- 
Unabashedly littering the information superhighway with detritus like
this for over 15 years now.