I installed a brand new WD Red 6 TB Pro to replace a very old 3 TB parity drive. I installed it and selected it as the parity drive. It got through about 12 percent of the process, when I realized I did not preclear the drive. So I canceled the parity synch.

 

I've tried many times to preclear in a screen, using this command: ./preclear_disk.sh -a /dev/sde

 

I get the following:

 

^{BLKRRPART: Input/output error}

^{Sorry: Device /dev/sde is not responding to an fdisk -l /dev/sde command.}

^{You might try power-cycling it to see if it will start responding.}

 

I have power-cycled the drive and the computer many times, with the same result. When I run:

 

fdisk -l /dev/sde

 

I get:

 

^{WARNING: GPT (GUID Partition Table) detected on '/dev/sde'! The util fdisk doesn't support GPT. Use GNU Parted.}

 

Any suggestions as to how I get past all this?

 

Thanks.

 

 

Apparently you have a GPT formatted disk

Follow these instructions and clean it and change it back to a MPR partition disk

Thanks thestewman. Did you mean to link to the instructions?

 

Apparently you have a GPT formatted disk

Follow these instructions and clean it and change it back to a MPR partition disk

The existing format of a disk should be irrelevant when preclearing a disk as it gets wiped anyway.

 

I wonder if it is a side-effect of the -a option which is not relevant for large disks (and I thought was ignored)?

Unfortunately, running preclear with not options (./preclear_disk.sh /dev/sde) results in the same error.

 

I attempted to "zap" the drive using gdisk advanced. Here's the result:

 

^{Expert command (? for help): z}

^{About to wipe out GPT on /dev/sde. Proceed? (Y/N): Y}

^{Warning! GPT main header not overwritten! Error is 5}

^{Warning: The kernel is still using the old partition table.}

^{The new table will be used at the next reboot.}

^{GPT data structures destroyed! You may now partition the disk using fdisk or}

^{other utilities.}

 

I reboot the box (which seems to take a long time), try preclear again, and get the same error. I am guessing the "Warning! GPT main header not overwritten! Error is 5" may provide a big clue, but I'm not able to find an answer to it.

 

I wonder if there is some basic incompatibility with these disks?  I know that the WD Red RE disks seem to be incompatible with unRAID.  Not heard this for the WD Red Pro disks but there might be an issue I guess.  I do not think we have much experience as most users are not prepared to pay the premium prices for these drives.

I wasn't ready to pay the premium either. It was at $269 on Amazon about a week ago, which was only $25 more than the non-pro version. So I pulled the trigger after reading 1-2 posts here of people using it. I could return it and get the 5400 RPM version, but I would like to exhaust all possibilities first.

 

One thing I'd like to rule out (particularly before I return it if I have to): Could the fact that I started a parity sync, got about 12 percent into it and cancelled to do the preclear have caused a problem?

Try the new preclear beta plugin, it's different so maybe it works:

 

http://lime-technology.com/forum/index.php?topic=39985.msg453938#msg453938

I wasn't ready to pay the premium either. It was at $269 on Amazon about a week ago, which was only $25 more than the non-pro version. So I pulled the trigger after reading 1-2 posts here of people using it. I could return it and get the 5400 RPM version, but I would like to exhaust all possibilities first.

Fair enough!

 

One thing I'd like to rule out (particularly before I return it if I have to): Could the fact that I started a parity sync, got about 12 percent into it and cancelled to do the preclear have caused a problem?

Actually the fact it got as far as 12 percent is a good sign as it should mean that the system does support this drive type.  Cancelling a parity sync is something you can safely at any point so that should not have been the cause of the problem.

 

The only thing to suggest at this point is to plug it into a Windows system and run the WD diagnostic tools against it to check it out.  It is always possible it really is defective.

It shouldn't be using fdisk, only gdisk or sfdisk.  Are you sure you are using an up-to-date version of the preclear script?

Did you try the new plugin I linked above?

Thanks thestewman. Did you mean to link to the instructions?

 

Sorry. Thought it was posted.

 

 

Follow instructions for Cleaning a disk and then make it int a MPR disk.

 

http://www.howtogeek.com/215349/how-to-remove-an-efi-system-partition-or-gpt-protective-partition-from-a-drive-in-windows/

Thank you johnnie.black and thestewman.

 

Converting the disk to MBR and then using the new preclear beta seems to have done the trick. The 6 TBs are busy preclearing, and I hope to have all in order in, well, a couple of days now.