What is the "special signature" that preclear sets for unraid?  Can it in any way be interpreted as a partition?

 

I have a couple of older disks that were in linux and freebsd systems a long time ago, and tried to use them with esxi, but esxi freaked out about partitions (couldn't delete them) and I had to put the disks in a Windows machine to nuke them from orbit before I could use the disks.

 

I am going to create a raid5 array with four disks and would like to torture test said disks before I commit them to the array -- was thinking of using preclear to do so.  I am ordering five disks from the same vendor and anytime I order that many disks from one place, I get nervous about the failure rate percentage going up (they are enterprise drives and a vendor on flea-bay has qty discounts that beat the pants off everyone else, so I can't mix and match vendors like has been suggested here to avoid drives from the same mfg lot etc).

 

Wondering what grief I can expect from the raid controller and/or esxi if I use preclear.  Alternative method recommendations most welcome.

 

Thanks.

I'm not sure about the special signature bit (personally never had problem reusing drives as I always clear their partition table first), but if you want to torture drives you can also use badblocks. It writes different patterns to the drives and reads them back, noting (if any) badblocks along the way. The list of bad blocks can be fed to mkfs so the badblocks are skipped/not used.

 

http://en.wikipedia.org/wiki/Badblocks

Yes - you can use pre-clear to test a disk regardless of where it is going to finally be used

 

The pre-clear process DOES write an unRAID compatible partition structure to the disk as part of the write phase.  In theory this should not upset any other system but if you want to play safe you can remove this either using the gdisk partitioning utility, or by using dd to overwrite the first few sectors on the disk with zeroes (which zaps the partition information).

You can, of course, use pre-clear to test the disks.    I don't think you'd have any problem using them after that; but if you do, just connect them to a Windows box; run WD's Data Lifeguard; and do a Write Zeroes to the disk -- you can use the Quick method, which only writes the key areas (just takes a few seconds) -- this will make the disk look completely blank with no initialization or partitions.