StatsDawg

This graph shows the number of I/O operations currently in progress or waiting to access the disk. Though this data is averaged over time, it is only collected a choice intervals and so the graph may not be as accurate as the other disk graphs, but does represent sustained activity on the disk. Very high spikes in the graph may indicate times where the disk has becomee a bottleneck for the system, although this is likely to vary over different drive technologies (IDE vs SATA for instance) and different server configurations.