Best way to upgrade parity and replace failing drive?

[pyrater]

So i have a 3 TB drive dying:

 

187

Reported uncorrect

0x0032

098

098

000

Old age

Always

Never

2

197	Current pending sector	0x0012	100	099	000	Old age	Always	Never	136
198	Offline uncorrectable	0x0010	100	099	000	Old age	Offline	Never	136

 

My current server has two 3 TB Parity drives, however due to price point and the ability to upgrade later i bought two 8 TB drives to fix the problem. My logic is to take one of the 8 TB drives and replace one of the good 3 TB parity drives. RESYNC. Then take the pulled 3TB old parity drive and replace the failing 3 TB drive and RESYNC. Finally take the last 3 TB pairty drive and replace it with the other 8 TB Drive. and RESYNC. 

 

Is this the best method / way to do this??? This is going to take 3-5 days due to the multiple re-builds.

 

 

OR Would it be better to just go down to 1 pairty drive and use the other to replace the failing drive, once rebuilt, replace the remaining parity disk with both 8 TB drives?

Edited February 27, 2018 by pyrater

[JorgeB]

Either way works, you can also use the parity swap procedure.

[JonathanM]

Personally I wouldn't rebuild parity with a failing data drive.

 

I'd have to think through it a little more thoroughly, but my gut instinct is to use parity 2 to replace the bad drive, then add an 8TB as parity 2, let it build, check parity, then build parity 1 on the second 8TB.

[JonathanM]

2 minutes ago, johnnie.black said:

use the parity swap procedure.

That sounds like a better idea to me.

[JorgeB]

2 minutes ago, jonathanm said:

Personally I wouldn't rebuild parity with a failing data drive.

Since he's using dual parity it's not a problem, unless another disk fails, but would also recommend using the parity swap procedure.

[tdallen]

Do you have sufficient available space on the remaining data drives to copy the contents of the failing data drive?

[JonathanM]

43 minutes ago, johnnie.black said:

Since he's using dual parity it's not a problem, unless another disk fails, but would also recommend using the parity swap procedure.

So if the failing drive starts giving back corrupt data during the rebuild, the second parity will correct it? (I know, I know, very low probability, etc)

[JorgeB]

6 minutes ago, jonathanm said:

So if the failing drive starts giving back corrupt data during the rebuild, the second parity will correct it?

If there's a read error on the failing drive parity2 will be used to compute (and write back) the correct sector(s) data.

 

Same happens if for example a second disk (or the parity disk) fails during another disk rebuild, at least it did in all the tests I did always returning the correct data, doesn't mean it can't on some occasions return incorrect data (as sometimes happens when a disk fails during a correcting parity check), so a checksum check would still be recommended after.

[pyrater]

There are errors on Disk 6 so ill do the parity swap procedure. Thanx for the suggestions guys.  Can i do both Parity disks at the same time? Or do i need to do ONE, then swap the other?  IE:

1. Stop the array (if it's started)
2. Unassign the old drive (if it's still assigned)

   If the drive was a good drive and notifications are enabled, you will get error notifications for a missing drive! This is normal.

3. Start the array (put a check in the Yes I want to do this checkbox if it appears (older versions: Yes, I'm sure))

   Yes, you need to do this. Your data drive should be showing as Not installed.

4. Stop the array again
5. Power down
6. [ Optional ] Pull the old drive

   You may want to leave it installed, for Preclearing or testing or reassignment.

7. Install the new drive
8. Power on
9. Unassign the parity drive (BOTH!??)
10. Assign the new drive in the parity slot (BOTH!??)

    You may see more error notifications! This is normal.

11. Assign the old parity drive in the slot of the old data drive being replaced

    You should now have blue drive status indicators for both the parity drive and the drive being replaced.

12. ASSIGN THE OTHER (OLD) PARITY DRIVE AS ADDITIONAL STORAGE??

13. Go to the Main -> Array Operation section

    You should now have a Copy button, with a statement indicating "Copy will copy the parity information to the new parity disk".

14. Put a check in the Yes I want to do this checkbox (older versions: Yes, I'm sure), and click the Copy button

    Now patiently watch the copy progress, takes a long time. All of the contents of the old parity drive are being copied onto the new drive, then the remainder of the new parity drive will be zeroed.
    The array will NOT be available during this operation!
    When the copy completes, the array will still be stopped ("Stopped. Upgrading disk/swapping parity.").
    The Start button will now be present, and the description will now indicate that it is ready to start a Data-Rebuild.

15. Put a check in the Yes I want to do this checkbox (older versions: Yes, I'm sure), and click the Start button

    The data drive rebuild begins. Parity is now valid, and the array is started.
    Because the array is started, you can use the array as normal, but for best performance, we recommend you limit your usage.
    Once again, you can patiently watch the progress, takes a long time too! All of the contents of the old data drive are now being reconstructed on what used to be your parity drive, but is now assigned as the replacement data drive.

 

https://lime-technology.com/wiki/The_parity_swap_procedure

[JorgeB]

Parity swap only works with Parity1.