Synthetic data, sha, for test and reconfigs

[purduephotog]

I looked but did not see any accepted process for filling up a nas to test a hypothetical dead drive and resilver.

I could use a modified random dd command similar to the speed test to generate z number of files and names.

Suggestions? I have 8x 2tb drives in raidz2.

(Frankly the data loss threads have me freaking out, hence the reasons I want it tested.)