May 15, 201511 yr Hi, I tried the search, but couldn't find what I was looking for. I'm currently pre-clearing three drives and started the process with three cycles in mind. This has been going on for over 20 hours now and I'm wondering if I could just abort the pre-clearing after one cycle and be done with it... will I still get the results? Is one cycle enough? Thanks, D.
May 15, 201511 yr No, because the signature hasnt been written yet, or it overwrites with each pass...I dont know which.
May 15, 201511 yr There's no way to abort precisely at the end of a cycle. I think you could safely abort during the post-read, but not sure how safe it would be to abort anywhere else, without ensuring the correct signature is written, not overwritten as he said. There is a Preclear option to test for correct signature, and a dangerous option to write it, but you have to be absolutely sure the drive is fully zeroed, and correct MBR and signature written.
May 15, 201511 yr Hi, I tried the search, but couldn't find what I was looking for. I'm currently pre-clearing three drives and started the process with three cycles in mind. This has been going on for over 20 hours now and I'm wondering if I could just abort the pre-clearing after one cycle and be done with it... will I still get the results? Is one cycle enough? Thanks, D. IMHO, one cycle is enough. If the one cycle shows problems, I might then attempt another one to see if the issue resolves. There is a survey thread somewhere in which people report number of disks that failed after multicycle preclears that may help you make your decision. As I said, personally I'm good with one cycle.
May 15, 201511 yr Author There's no way to abort precisely at the end of a cycle. I think you could safely abort during the post-read, but not sure how safe it would be to abort anywhere else, without ensuring the correct signature is written, not overwritten as he said. There is a Preclear option to test for correct signature, and a dangerous option to write it, but you have to be absolutely sure the drive is fully zeroed, and correct MBR and signature written. Are you saying I would render my drive unusable, if I abort at the wrong moment? Am I understanding this correctly?
May 15, 201511 yr There's no way to abort precisely at the end of a cycle. I think you could safely abort during the post-read, but not sure how safe it would be to abort anywhere else, without ensuring the correct signature is written, not overwritten as he said. There is a Preclear option to test for correct signature, and a dangerous option to write it, but you have to be absolutely sure the drive is fully zeroed, and correct MBR and signature written. Are you saying I would render my drive unusable, if I abort at the wrong moment? Am I understanding this correctly? No, not at all. It just wont have the signature necessary to add it to the array.
May 15, 201511 yr Here is a link to the survey thread I mentioned. http://lime-technology.com/forum/index.php?topic=12616.0 I have precleared a LOT of disks. Had 2 or 3 fail in preclear single cycle. But I tend to buy HGST drives, and these have very good reliability stats. If I were buying a reliability challenged (e.g., Seagate drive 3T) drive, I might do more. But for reliable drives, one cycle gives me the most bang for the buck and is enough for me to weed out defective or damaged in shipping drives. If it comes out clean, unRAID's parity mechanism protects me from there.
May 15, 201511 yr Let it run I've had a WD RED 4T failed miserably, nuclear, just 12 hours after a single perfect preclear.
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