Section 4.18. DTraceTazTool

4.18. DTraceTazTool

TazTool^[13] was a GUI disk-analysis tool that used TNF tracing to monitor disk events. It was most notable for its unique disk-activity visualization, which made identifying disk access patterns trivial. This visualization included long-term patterns that would normally be difficult to identify from screenfuls of text.

^[13] See http://www.solarisinternals.com/si/tools/taz for more information.

This visualization technique is returning with the development of a DTrace version of taztool: DTraceTazTool. A screenshot of this tool is shown in Figure 4.8.

Figure 4.8. DTraceTazTool

The first section of the plot measures a ufsdump of a file system, and the second measures a tar archive of the same file system, both times freshly mounted. We can see that the ufsdump command caused heavier sequential access (represented by dark stripes in the top graph and smaller seeks in the bottom graph) than did the tar command.

It is interesting to note that when the ufsdump command begins, disk activity can be seen to span the entire sliceufsdump doing its passes.