I recently purchased new 4tb drives to get more space.  I disabled one 2tb drive, shutdown the pc, installed the new 4tb drive, however when I go to assign the disk unraid is reporting that the drive capacity is 4.6tb and wants me to replace the parity with the 'larger' drive.  I ran preclear which reported the drive to be 5tb, and clear completed successfully.

 

How is this possible?  I'm concerned that if I move forward using the '4.6'tb drive as parity that the data will be corrupt because it isn't 4.6tb or 5tb.  I have the same result with another brand new 4tb drive.

 

I should also point out that before replacing the drive I updated unraid to 6.6.3.  Any and all help/suggestions would be greatly appreciated.

Post your setup please. Including current situation and future situation after change or add new drives.

 

Parity must be at least same or bigger than biggest data drive.

 

Have a look on my signature. My backup server has 5 identical drives of each 4TB, Toshiba MD04ACA400. My media server has different drives, parity is a WD with 4TB, data drives are a bunch of 2TB, 3TB and 500GB.

Please post your diagnostics: Tools -> Diagnostics

2 hours ago, ducksheeta said:

I recently purchased new 4tb drives to get more space.  I disabled one 2tb drive, shutdown the pc, installed the new 4tb drive, however when I go to assign the disk unraid is reporting that the drive capacity is 4.6tb and wants me to replace the parity with the 'larger' drive.  I ran preclear which reported the drive to be 5tb, and clear completed successfully.[/quote]

 

How is this possible?  I'm concerned that if I move forward using the '4.6'tb drive as parity that the data will be corrupt because it isn't 4.6tb or 5tb.  I have the same result with another brand new 4tb drive.

 

I should also point out that before replacing the drive I updated unraid to 6.6.3.  Any and all help/suggestions would be greatly appreciated.

Are you sure it is not a 5TB drive?    Posting the requested diagnostics will show the model number so that this can be checked.  Alternatively a screen shot should show the model number information.

 

Unraid will not let you assign a drive as parity that that is larger than the data drives so you cannot get 'corrupt parity' in the way you suggest.

 

It is also worth pointing out that the current release is 6.6.5, not 6.6.3.

Sorry for the late response everyone.  I've attached my diagnostic. I'm sure its a 4tb drive.

 

I'm fine with assigning the new drive to the parity, I guess I am just concerned that I could potentially be trying to write to space that isn't there.

ducksheeta-diagnostics-20181126-1030.zip

Not seen that model drive before. Some googling suggests it is a fantom brand external drive.

 

And SMART is reporting it as 4.6TB

So I was probably sold a piece of... with a fancy label put on it.  Ok, I'll probably just return these.  Thanks everyone!

There's a company called MaxDigital that refurbishes WD drives (and possibly Seagate too) and puts their own label on them. You see them on Ebay (this one's fairly obviously a WD) and AliExpress. Maybe its one of those - your other MD4000s seem to be. Do you have a photo of it?

You're 100% correct.  The label says MaxDigital.

They are probably no worse than drives refurbished by WD themselves. Maybe what you have started out as a 5 or 6 TB drive but MaxDigital have limited it to 4.6 TB to avoid an area of platter damage. I see they install their own firmware, so that's possible. In selling it as a 4 TB drive they're doing the "decent thing" and you get the bonus of a bit of extra space for free. I'd use it for backups but not in my array. You could use it as a data disk if you want to, but I wouldn't try to use it for parity. I hope it was significantly cheaper than a WD branded 4 TB drive.