Server Building > Hard Drives and Controllers
Preclear and Failed Drives
opentoe:
I'll take a long data re-build a good clear for me. If the drive is going to fail right away, it will during a re-build. A drive can fail at any given time.
Rajahal:
--- Quote from: opentoe on May 19, 2011, 07:44:22 PM ---I'll take a long data re-build a good clear for me. If the drive is going to fail right away, it will during a re-build. A drive can fail at any given time.
--- End quote ---
I don't think that is true. A data rebuild will write to the entire drive, so that's good. But it won't read from it. A data rebuild followed by a parity check would be better in my opinion, but still not as good as a full preclear (which is a read, then a write, then a read again). The preclear also tests both sequential and random writes/reads, whereas the data rebuild + parity check would only test sequential writes/reads.
madburg:
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.
BRiT:
Somehow I never noticed this thread until now.
I run 3 or more preclear cycles on my drives and I've seen drives pass the first cycle but failed hard in the second cycle. The third cycle confirmed that the drives were toast. It even failed the smart short test with read failures!
0bit:
Hello all
I guess this is good as any for a first post. I precleared 20 2tb drives and a 500gb cache drive 3 cycles each and there were no errors.
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