Advanced Format Drives - WD10EARS WD15EARS WD20EARS


Recommended Posts

There is risk in this procedure, proceed with caution.  If you have any disks you don't trust, then don't do this.  You must do the following on one drive at at time:

 

1) Run a parity check.  If there are any errors, DO NOT PROCEED.  Instead, seek help here.  You want to make sure your array is healthy before you attempt this.

2) Stop the array, go to the devices page, and unassign the unaligned disk.

3) Start the array.  unRAID will tell you there's a missing disk.  The array will now be running in degraded mode (meaning you have no parity protection if another drive were to fail at this point).

4) Run Joe's preclear script with the -A option to align the disk.

5) Once preclear is finished, assign the now aligned disk to the empty drive slot (the same slot it previously occupied)

6) Start the array.  unRAID will start a data rebuild and reconstruct all the contents of the unaligned disk onto the aligned disk.

7) Once the data rebuild is complete, run another parity check.

 

That same procedure would work if you were replacing an unassigned disk with a brand new disk, the only difference being that you could preclear the new disk before starting this whole thing and minimize the amount of time you have to run in degraded mode.

Link to comment
  • Replies 284
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Using that procedure will leave you in degraded state for 2 days, since the preclear with the -A option itself will be 33+ hours plus you'll need another 8 to 10 to re-construct the data onto the drive itself.

 

If your disks are working... My advice, don't mess with them.  The risk of loss of data is high.  All it would take is ANY write error on ANY other disk to lose the contents of BOTH disks.

 

Joe L.

 

 

Link to comment

Joe, assuming the unaligned disk is trustworthy, could one use the -n option (to skip the preread) in addition to the -A option to minimize unprotected array time?  Any other options that would make this quicker and safer?

 

I'm inclined to agree with you - if the disks are working and there aren't any overt issues, just don't mess with it.

Link to comment

thanks guys...I truly appreciate your input.  I am going with the "new drive" scenario.  I am preclearing with -A on a new 2TB EARS.  Once complete I will remove the "incorrect" drive.  I will insert the new drive into the same slot physically in the server.  After that I will bring up the server and it will try to restart, but be lost due to a missing drive.  Not sure if it will start automatically, but will then stop it if necessary.  I then assign the new drive to the "old" disk designation and let the data reconstruct begin.

 

Will I be able to verify the MBR 4k format prior to the reconstruct?  I assume so once I assign it to the slot.

Link to comment

I have two 2TB EARS drives. One I had installed for a few months and another I just recently added. As I was adding the new drive, the old one developed problems (Unraid said the disk was invalid). I had just precleared the new drive (no jumper, no -A option as I didn't know about all this fuss) so I replaced it without any problems. I decided I'd try to preclear the old disk to see what was wrong with it. I ended up getting some input/output error, the preclear failed, and then the disk would not report itself using the -t command (I'd just get two rows of ***** with no information between). If I rebooted the server, the disk would come back. Upon reading this forum I've upgraded to Unraid 4.7 and to the latest preclear. I attempted to run the -A option on the same drive (again, no jumper), and I got the attatched error message stating the smartctl does not recognize the drive. It appears I am running smartctl 5.38 and apparently 5.39 exists, but I searched this forum and did not find any mention of upgrading. Do I need to upgrade? Thanks!

preclear-smartctl-unrecognized-drive.txt

Link to comment
  • 5 years later...

Sorry to bump an old thread, but I'm hoping someone from this era has some insight, and this will jog some memories.

 

I freed up one of these drives from an old desktop and through I'd add it to my 6.1.8 array.  I precleared it with Unassigned Devices (so no fancy switches) and the final report indicates the starting sector is 64 (all the other drives report the starting sectors as 1).  And adding it to the array shows "MBR: 4K-aligned (factory-erased)" So all is well?  Nothing more I need to do for optimal performance?

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.