Swap array disks with another unraid server (New Config)

[AndrewT]

I have two unraid servers but one holds half the disks/slots, so I need to physically swap the array disks. I'd like to keep my cache and usb drives where they are. I can't backup my array data until this is done, so I just wanted to make sure I fully understand the process.

 

Johnnie Black had a recent post that helps but just want clarity from this, because I can't see what options I have after clearing the disk config until I do so: 

1) For each server, save the info listed in the webGUI's Main of "Device" and "Identification" mappings.

2) Use the webGUI's Tools -> "New Config" for each server, which wipes the flash drive's memory of which disks are parity, cache, and array. Where is the file stored by default?

3) Power down both servers

4) physically swap the array disks only

5) power back up and boot into unraid

6) now in the "Main" section there will be drop-down menus for each disk to add, so add according to the saved list (keeping the current cache and flash drives as-is)

7) an option before starting the array on the Main will have a check box to say "Parity is already valid" so check that

8.) run full parity check with write errors to parity disks for both servers

9) if few to no errors, then start using arrays

 

Steps 6 and 7 I'm most worried about, because I remember seeing that check box option for parity already valid in unraid5 but don't remember seeing it in unraid6.

 

Does the disk # matter for parity disks (I have dual) or for array disks?

[Frank1940]

17 minutes ago, AndrewT said:

Does the disk # matter for parity disks (I have dual) or for array disks?

You MUST assign the parity disks (Parity and Parity 2) EXACTLY as they were in the original server by using the serial numbers of the disks.   Data disks can be in any order unless you had shares excluded from using some disks (or allow to store data on only some disks)  and want to retain those settings.   In any case, it always best to do a printout of the current disk assignments just to be certain that the disks have been assigned to the proper class (Parity, Parity 2 and Data) before you start the array for the first time.

[JorgeB]

If you're going to do a swap it would be easier to just swap super.dat on both flash drives (config folder), but first disable auto array start if enable, then swap super.dat after the servers are cleanly shutdown, finally start the servers with the swapped disks and check that all array disks are assigned correctly including valid parity, you'll just need to reassign both cache devices.

[JorgeB]

P.S. after the swap make sure filesystem for each disk is set to auto or the correct filesystem, or you can get unmountable disks if they are set to a specific filesystem and it's different than it was on the other server.

[AndrewT]

Thanks! It's especially useful to know the parity numbered disks do matter.

 

The config/super.dat is a binary file... no wonder grep -e 'WDC_' -e 'HGST_' -e 'ST4000' didn't work anywhere in the flash that I looked

 

edit: After each server was shutdown, moving the super.dat files between the server flash drives worked well. After booting up (autostart array turned off on both), it allowed me to change the cache disks before starting the array.

Edited January 28, 2018 by AndrewT