[SOLVED] Best way to remove a parity drive

[hanabi]

Using unRAID Server Pro version: 5.0-rc5.

 

My current unRaid array has 25TB 10 disks plus a 4TB parity drive. I recently built another 25TB NAS using Drive Bender and copied the entire unRaid array to it, so I now have a redundant system. I'm thinking there is now no need to keep the parity drive and its associated slow write speed, and would like to use it as a data drive in unRaid. Could someone please offer suitable advice as to the steps required to make a parity drive a data drive in unRaid? Here's what I think I should do:

 

1. stop the array

2. unassign the parity drive

3. assign the parity drive to a data drive slot

4. ? ? ? automatic zeroing/formatting  by unRaid of the old parity drive to make it a data drive?

5. start the array

 

Is it preferable to run the pre-clear script on the parity drive prior to step 3? It was pre-cleared when initially inserted into the array.

 

A second, unrelated question if I may. Is there an unRaid utility/add-on that will list the files that are possibly corrupt when a parity error is detected? My understanding is that, when a parity error is detected, unRaid cannot determine which file/disk has the error, so it simply corrects the parity drive. I have run CRC/MD5 checks of all my files, so when a parity error is detected it would be nice if I could check for corruption just those files that may be corrupt, rather than checking every file on the array.

 

When it comes to unRaid I am still quite a beginner so I appreciate any help with the above questions.

 

Hanabi

[garycase]

You're correct r.e. the process of removing the parity drive ... and since it was already pre-cleared AND has been used as a parity drive I don't see any reason to do another pre-clear.

 

However ... you DO realize that removing the parity protection from your array means you will no longer be fault-tolerant -- and would thus lose data in the event of a drive failure.

 

[dgaschk]

Select Utils->New Config. Then reassign the drives. The parity drives assigned as a data drive will not need to be zeroed. It should just take a minute to format it.

[hanabi]

Thanks for the replies guys.

 

So, in summary:

 

1. stop the array

2. select Utils->New Config

3. unassign the parity drive

4. assign the (unassigned) parity drive to a data drive slot

5. start the array

6. wait for formatting to complete.

 

If there are no more comments I'll give this a try tomorrow.

 

<<However ... you DO realize that removing the parity protection from your array means you will no longer be fault-tolerant >>

 

Yes, I understand that. I now have a second NAS with a complete backup of my data.

 

Thanks again 

 

Hanabi.

 

[itimpi]

It is worth pointing out that if you have actually used the parity drive it is effectively no longer in the pre-cleared state.  This means if you then add it as a parity drive you would have the array offline while unRAID pre-cleared the drive.  You therefore probably want to consider pre-clearing it before adding it in as a data drive.

[JonathanM]

It is worth pointing out that if you have actually used the parity drive it is effectively no longer in the pre-cleared state.  This means if you then add it as a parity drive you would have the array offline while unRAID pre-cleared the drive.  You therefore probably want to consider pre-clearing it before adding it in as a data drive.

pre-clear only matters if the array is protected by parity. I do not know if the unraid engine is smart enough to know it shouldn't care about the preclear signature if there is no valid parity to preserve. Theoretically you should be able to just add the drive and format it, as there will be no parity drive.

[garycase]

Jonathan is correct -- since there's no parity drive, there's no need to pre-clear the drive.  It will simply need to be formatted ... which would be true even if it was pre-cleared.

[dgaschk]

Clearing is not performed without a parity drive.