Anyway to remove (w/o replace) multiple disks without losing parity?

[WobbleBobble2]

Hello! 

I had listed my old NAS with drives on ebay for a few months with no takers and gave up on it ever selling so pulled 5 8tb drives out and cleared and put them into my new Unraid server. Clearing is done and they are now mounted in the array. I have already used Unbalance to remove all data from them, so all 5 are completely empty and all 5 have been removed from global shares and all individual shares.

 

Literally a day after doing this someone bought my old NAS so now I need to remove those 5x 8tb drives. I am risk averse and really do not want to do the "remove drives then rebuild parity" option here: https://docs.unraid.net/legacy/FAQ/shrink-array/#for-unraid-v62-and-later

 

This option would mean I would have no parity protection for a very long and intensive rebuild process which would be super scary. 

 

Option 2 "Clear Drive Then Remove Drive" would be fine except I can only do 1 drive at a time and 5 8tb drives will likely take a month. Way too long to expect my eBay buyer to wait. 

 

Is there any way for me to simultaneously zero all 5 disks at once without losing parity? Any help would be hugely appreciated! 

 

I tried to attach diagnostics to this post, but my diagnostics tab keeps crashing before the download starts (something to deal with in another thread I suppose). 

 

Other basic stats on the array:

Dual parity

5 disks to keep, 14-20tb

5 8tb disks to remove

12500k

[JorgeB]

9 minutes ago, WobbleBobble2 said:

Is there any way for me to simultaneously zero all 5 disks at once without losing parity?

No, but with with turbo write it should take less than a day to zero an 8TB disk, assuming no controller bottlenecks.

[WobbleBobble2]

Thanks so much for the quick reply. This is a bummer but I will try one 8tb first and see how it goes. 

[WobbleBobble2]

Hey Jorge, I found this thread from a year ago which is saying the script doesn't work out of the box. You had commented about making a change to a command. 

 

Do I still need to make that change?

 

[WobbleBobble2]

56 minutes ago, JorgeB said:

No, but with with turbo write it should take less than a day to zero an 8TB disk, assuming no controller bottlenecks.

Ok I just tried running the script and I am getting some wierd results. The whole clearing only took like 30 seconds:

Script location: /tmp/user.scripts/tmpScripts/clear an array drive/script
Note*** Clear an unRAID array data drive *** v1.4

Checking all array data drives (may need to spin them up) ...

Found a marked and empty drive to clear: * Parity will be preserved throughout.
* Clearing while updating Parity takes a VERY long time!
* The progress of the clearing will not be visible until it's done!
* When complete, Disk 6 will be ready for removal from array.
* Commands to be executed:
*****
You have 60 seconds to cancel this script (click the red X, top right)

Unmounting Disk 6 ...
Clearing Disk 6 ...
dd: error writing '/dev/md6': No space left on device
9+0 records in
8+0 records out
8388608 bytes (8.4 MB, 8.0 MiB) copied, 0.00190806 s, 4.4 GB/s

A message saying "error writing ... no space left" is expected, NOT an error.

Unless errors appeared, the drive is now cleared!
Because the drive is now unmountable, the array should be stopped,
and the drive removed (or reformatted).

 

And now disk 6 says it's only 16gb instead of 8tb:

 

Also there is nothing in disk 6 - the "clear-me" folder has been removed. 

Edited June 11 by WobbleBobble2
formatting

[JorgeB]

I don't recommend the script, even when it works looks like it's very slow, at least for most users, you can do it manually:

 

https://forums.lime-technology.com/topic/61614-shrink-array-question/?tab=comments#comment-606335

 

 

[WobbleBobble2]

11 minutes ago, JorgeB said:

I don't recommend the script, even when it works looks like it's very slow, at least for most users, you can do it manually:

 

https://forums.lime-technology.com/topic/61614-shrink-array-question/?tab=comments#comment-606335

 

 

Shoot I already used the script on 2 drives. Any chance you can take a look at the output in my earlier post (disk 6) and help me understand what happened? How is it possible it completed so fast? Could it be because the disk was just precleared? Any way for me to confirm whether the zeroing was completed successfully other than the script messaging saying it was done correctly? 

[JorgeB]

13 hours ago, WobbleBobble2 said:

Any chance you can take a look at the output in my earlier post (disk 6) and help me understand what happened?

The disk wasn't cleared, it failed because it used md6 instead of md6p1