Reading articles on the web (here's an example) shows interpretation of the Load Average element of uptime to be far from simple, but I wondered what a "High" Load Avaerage is for the MyBook White Lights when running RAID1?
To mimic the heaviest load mine is likely to get, I simultaneously ran backup verifications to it from each of three PCs (Backups are held on the NAS HDDs), streamed three separate music streams to different devices (music is also on the NAS HDDs), and streamed two MPEG4 movies from the USB HDD plugged in to the NAS (so separate HDD but the NAS CPU still has some work to do).
Whilst this was going, every minute I wrote the Load Average for the previous one and fifteen minutes to a log file. The result was 1.24 to 1.29. During this activity all the streams worked seamlessly, movie scene "jumping" was near instantaneous like usual, and using Windows Explorer to navigate folders in the Data Volume or WinSCP to jump around was absolutely as zippy as when the NAS is otherwise idle.
At the other extreme, letting it run back to idle and then just giving it one music stream to handle gave a Load Average of 0.08 to 0.10.
Just interested, that's all.