I thought I would make a separate topic about this issue as it may affect others in the future.  I was having trouble preclearing a drive when I noticed that my list of drives looks different from the example.  Instead of sda, sdb, sdc, etc.  I have sda, sda1, sda2, sdc, sdc1, sdd, sdd1, and sde.  There are four drives in the machine at the moment.  I'll attach a screenshot.  The only thing I can think of is that my drive sda which won't preclear is already partitioned and giving the system trouble.  Is this correct?  If so, do I need to put it in another machine to remove the partition? 

 

Thanks for your help as always. 

The base name sda, sdb, sdc, etc, is used by the operating system to access the entire disk, regardless of its partitioning.

 

A specific partition is accessed through the base-name with the added numeric suffix. 

/dev/sda1 = first partition on /dev/sda

/dev/sda2 = second partition on /dev/sda

/dev/sda3 = third partition on /dev/sda

 

Existing partitioning will not cause unRAID issues.  unRAID either recognizes it as valid for unRAID, and uses it (when initially setting up an array)

Or, it re-partitions it (if not recognized) when a disk is assigned to the array.

 

When adding a disk to an array already protected by parity, the new disk partition is completely written with zeros before allowing the array to use it.  If "pre-cleared" this is skipped since the array knows it already contains zeros as expected.

 

None of this has anything to do with pre-clearing a drive, although the pre-clearing process will add a pre-clear-signature to the disk and that does make it look to most Linux utilities as if the disk has been partitioned.  (windows will not recognize it, but, that is to be expected)

 

The setting up of the pre-clear-signature is done only after the successful pre-clearing of the drive.  If it has not been successfully pre-cleared, no pre-clear-signature will exist, and it will not show the "partitioning" that is part of the pre-clear-signature.  In fact, the very first thing done by the "write phase" of the pre-clear process is to remove any existing partitioning.

(It writes zeros to the master-boot-record sector that holds the partition table on the disk)

 

You can print the partitioning on /dev/sda simply by typing

fdisk -lu /dev/sda

 

Based on your screen shot of unMENU, there are two existing partitions on /dev/sda.

 

Sounds more like a defective disk, disk controller, power supply issue, or something else involved with that disk.

 

If you wish to completely wipe the partitioning of that disk, there is an option to the pre-clear script that will zero the master boot record (and only it)  It will not be pre-cleared, but any trace of the old partitions will be gone.

preclear_disk.sh -z /dev/sda

 

Note that this just overwrites the partition table, it does not clear the drive.

Thank you very much for your detailed help!  I just finished putting that drive into another computer to see if it had any partitions, and it appeared not to, so I'm going to assume that there's something wrong with the disk and keep it out of my machine.  A shame. 

 

Again, thank you for your help.  I'll keep note of the information!