i have a 320BG western digital that i did a quick NTFS format in windows. when i install in unraid box do I need to pre clear it before i can use it as cache drive?

AFAIK Yes. Or Unraid will clear it for you.

You don't *have* to preclear any drives. In layman's terms, preclear stress-tests the drive and formats ready for UnRaid use. The question is can you afford to have the disk fail? Preclear clearly won't prevent this, but should weed out a disk that's on its last legs.

 

When answering this question, remember that a cache drive isn't part of the protected array, so isn't recoverable after a failure. On this basis, one could argue it is even more important to preclear.

 

IMHO, I preclear every drive before using in a production environment - yes, I can't start using the drive for 24hrs, but better this than losing data in the future.

AFAIK Yes. Or Unraid will clear it for you.

no, unRAID will not do anything to a cache drive but format it.  The first time you'll learn of un-readable sectors is when unRAID attempts to read it to move a file written to it to the protected array.  A bad sector them means you've lost potentially your only copy of a file to a defective sector.

 

Joe L.

One small correction.  Preclear does not format the disk.  It does leave a "preclear signature" that is used if you try to add the disk to the array.  But the preclear signature does no harm if you are going to use the disk as a cache disk or for any other purpose.

 

You don't *have* to preclear any drives. In layman's terms, preclear stress-tests the drive and formats ready for UnRaid use. The question is can you afford to have the disk fail? Preclear clearly won't prevent this, but should weed out a disk that's on its last legs.

 

When answering this question, remember that a cache drive isn't part of the protected array, so isn't recoverable after a failure. On this basis, one could argue it is even more important to preclear.

 

IMHO, I preclear every drive before using in a production environment - yes, I can't start using the drive for 24hrs, but better this than losing data in the future.

Thanks... that clears it up.

One small correction.  Preclear does not format the disk.  It does leave a "preclear signature" that is used if you try to add the disk to the array.  But the preclear signature does no harm if you are going to use the disk as a cache disk or for any other purpose.

 

You don't *have* to preclear any drives. In layman's terms, preclear stress-tests the drive and formats ready for UnRaid use. The question is can you afford to have the disk fail? Preclear clearly won't prevent this, but should weed out a disk that's on its last legs.

 

When answering this question, remember that a cache drive isn't part of the protected array, so isn't recoverable after a failure. On this basis, one could argue it is even more important to preclear.

 

IMHO, I preclear every drive before using in a production environment - yes, I can't start using the drive for 24hrs, but better this than losing data in the future.

 

From what I've seen, the formatting is done by UnRaid (when you hit the "Format" button in the GUI).  The preclear script writes the "I'm already precleared" signature after writing zeros to every sector on the disk (thereby stress testing it).  Having the signature there prevents UnRaid from doing the preclear itself (while your array is offline and unusable!).  But as Joe L. says, UnRaid won't "preclear" the cache drive like every other drive.  But doing the stress testing is a good idea before putting it into action handling your files.

 

lol i really do need to not try and say things.