Is it possible to run a 14TB parity drive with a 16TB in the array temporarily?

[rtgurley]

I know that the proper setup for unRAID is to have the parity drive be at least as large as all other drives otherwise you lose access to some of the space on the larger disks in the array.

My current setup is:

• Parity 14TB
• Array - 3 x 8TB, 3 x 12TB, 3 x 14TB

Here is what I ran into this weekend. I noticed my parity check was going painfully slow so I used the DiskSpeed docker to test my disks. 2 of my 8TB drives are reading very slow speeds. I decided that it was time to upgrade them with some 16TB plus use a spare 14TB spare I had on hand. The plan WAS to:

1. pull an 8TB from array, replace with spare 14TB and let rebuild
2. pull 14TB parity, replace with 16TB and let parity rebuild
3. pull 8TB from array, replace with 14TB and let rebuild
4. keep extra 16TB as a spare

Long story short the spare 14TB can't be read by 3 different computers, and the 8TB rebuild would take over a week. Currently I am running with my 8TB emulated.

My plan now is to put my new 16TB in the array and only use 14 TB (size of parity), then put the other 16TB in parity. If I do that will I get my 2 TB back automatically when the parity drive is installed? Is there a better solution to this?

 

I originally posted this in Reddit and 2 people have said that unRAID won't even let me use a 16TB drive in the array if parity is only 14TB.  I was always under the impression that if the parity drive was smaller it could be used, it would just limit the size of the drive to match the size of the parity drive.

[MAM59]

no way

UNRAID won't allow you to start the array with a data disk larger than parity disk.

[rtgurley]

Somebody on reddit shared this document with me.  So far I am about 74% (18 hours) into copying data from old parity to new parity.  This seems faster than having to redownload data and rebuild parity.

[itimpi]

56 minutes ago, rtgurley said:

Somebody on reddit shared this document with me.  So far I am about 74% (18 hours) into copying data from old parity to new parity.  This seems faster than having to redownload data and rebuild parity.

Not sure that version is still accurate as it is in the 'legacy' part of the documentation.   The current online documentation for that is here in the online documentation accessible via the Manual link at the bottom of the Unraid GUI.  In addition every forum page has a DOCS link at the top and a Documentation link at the bottom.