Is Parity Drive Swapping Possible?


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Fellow Forum Members,

My UnRaid array setup includes two 8TB Parity Drives and eight 8TB Data Drives for a total of 10 hard drives. 

 

Recently, Western Digital started selling 18TB GOLD hard drives.  I am thinking once the price goes down I will like to buy three 18TB drives. However, is re-configuring my UnRaid OS as shown in the bullet list below possible without breaking the entire UnRaid Array?

 

  • I want to format the two 8TB Parity Drives and convert them to Data Drives.
  • I want two new 18TB drives to take over as Parity Drives.
  • I want to add one 18TB drive as a Data Drive.

 

At the end of all this hard drive swapping around my UnRaid Array will have 13 hard drives. However, is the UnRaid OS flexible enough to accept such changes without breaking down? What is the correct way to swap two smaller capacity Parity Drives with two bigger capacity Parity Drives? Is there a risk of losing actual data by performing such a Parity Drive swap?  Any opinion welcome.

 

 

 

 

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I think you can just shutdown the pool, and add as many parity drives as you wish, if I remember correctly...  Once the new parity drives are up and running, you can use the "New Config" tool in the tools pane to take drives out of the pool, and just check the "Parity drive is already up to date" to turn the pool back on...  afterward, you can use the old drives as you see fit...

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13 minutes ago, Warrentheo said:

I think you can just shutdown the pool, and add as many parity drives as you wish, if I remember correctly...  Once the new parity drives are up and running, you can use the "New Config" tool in the tools pane to take drives out of the pool, and just check the "Parity drive is already up to date" to turn the pool back on...  afterward, you can use the old drives as you see fit...

Not much of this is correct. You can have a maximum of 2 parity disks. New Config will not be needed and should not be done.

 

Replacing a parity disk is like replacing any other disk. A disk can only be replaced with a disk of the same or greater size, and no data disk can be larger than any parity disk.

  1. Shut down
  2. Replace disk with larger disk
  3. Reboot
  4. Assign new disk to same slot
  5. Start array to begin rebuilding

You can replace and rebuild both parity at once, or do them one at a time and so maintain parity protection during the rebuild.

 

You can reuse the old parity disks as you want. If you use one to replace a data disk, the procedure is the same as above. The parity calculation provides the data for the replaced disk, whether replacing parity or data.

 

Or you can reuse a disk in a new slot. Unraid will clear the disk which will make it consistent with existing parity, then you can format it.

 

Please ask for further advice if any of this is unclear, and we can get more specific.

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Ah sorry, I knew it defaulted to 2 Parity, but I thought you could select more from a drop down underneath the 2 like you can with the data drives...  Haven't been able to shut my array down to double check...  Maybe you would want to replace and rebuild one drive at a time then, that way you are not without parity protection...  Just in case...

Edited by Warrentheo
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Thank you to all for your posts. It's good to know that as hard drives with greater capacity come out in the future, UnRaid Parity Drives have the ability to accommodate new hard drive technology.  I have decided it is smarter to just hold off on buying 18TB hard drives and just wait for the price to go down on them.   Once it does then I will rearrange my UnRaid array.

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