[SAC] Options for controlling I/O Bandwidth of backups etc

I've been pondering how we could better manage backup processes,
mirroring of downloads etc without the potential to slow everything down
to a halt. Aside from my idea on the wiki page to stagger backup times
between 3 distinct time segments;
See very bottom of

There seem to be some relatively easy to implement options.
A little research has revealed a few options
1. Limit the bandwidth on rsync processes
2. Use some tools to control QoS such as ionice

Any thoughts?