Great post/poll. I will not vote just yet...
I started my unRAID & preclear_disk experience as followed. I precleared many old drives which I will use at the end of my 24 drive unit. Once I exceed all available slot with 2TB drives I will then swap out my older drives. Squeezing my money worth for what I paid for these puppy's back in the day. (P.S. all Hitachi 7200k drives. 160Gb, 250Gb, 320Gb)
I was preclearing these old drives with 3 Passes, only one drive showed reallocated sectors from a very lond time ago and no new additions. So I thought this was the recommended. I then started purchasing my new Hitachi 2TB, first was a 7200k for parity and precleared it with three passes all was well, the second Hitachi was a 2Tb green drive, also 3 passes. All these drives were done in an old foxconn MB. When I moved them to my new supermicro MB with SAS controllers, i decided to run one more pass on each, I was not aware of the -D option in preclear and ended up with now SMART data in the reports... So I ended up running another pass on each with the -D option to get the SMART data in the reports. ALL still came up fine. Then I read a post here in the forums about what does 1 preclear pass equate to for a harddrive lifespan (workload)... i think most of us were surprised by Joe L.'s anwser. So my next (2)2TB Hitachi green drives I only ran 2 passes on and all is still well. I am waiting on 4 more 2TB Hitachi's and plain to do the same 2 FULL passes on each, if I see anything out side of 0,0,0,0's then I will apply more passes. And then I will vote in this poll.
Thank you for the great script Joe L., great post/poll guys! and love the forum as well as the maturing product unRAID! rocks.