Hi!

 

After replacing a drive by a bigger one, I need to go back to the previous configuration. How do I do this safely?

 

What I wanted to do:

Replace my 1.5 TB parity drive by a new 2TB parity drive and replace one of the 1 TB data drives in the array by the former parity drive.

 

What I did:

• Before I started, I did a parity check, which turned out OK. So I'm reasonably confident that the data drives are in good condition.
  
• I powered down the system, replaced the parity drive, restarted and let unraid do a parity synch.
  
• After that finished, I powered the system down again, replaced one of the data drives by the former parity drive and started a disk rebuild.
  

What happened then:

• I realized that my new parity drive had a firmware bug (Samsung F4) and the parity data wasn't reliable.
  
• I stopped the rebuild, powered down the system and replaced the 1.5 TB drive by the old 1 TB drive
  

My problem:

unraid tells me that the new disk (which is in fact the old disk) is to small.

So my situation is: I have a bunch of data disk, which I'm convinced are good. No parity data, but that could be rebuild if unraid would accept the old data drive.

 

So, am I right that I should:

• Tell unraid that it should accept the smaller drive.
  
• Rebuild the parity on the old (1.5TB) parity drive.
  
• Start over, once I get a new, reliable 2TB drive
  

If that's true, how do I do it?

I'm using 4.5-beta8 (Yeah, haven't updated in a while. Planned on doing it after the drive upgrade...)

Would

• Leaving the 1TB disk in the array.
  
• Replacing the parity drive by the 1.5TB drive. (Thus restoring the old configuration)
  
• checking "I'm sure I want to do this" and hitting "Restore"
  

be the right thing to do?

I guess I'll have to tell unraid to resynch parity after that.

 

Regards,

    myce

If that's true, how do I do it?

I'm using 4.5-beta8 (Yeah, haven't updated in a while. Planned on doing it after the drive upgrade...)

Would

• Leaving the 1TB disk in the array.
  
• Replacing the parity drive by the 1.5TB drive. (Thus restoring the old configuration)
  
• checking "I'm sure I want to do this" and hitting "Restore"
  

be the right thing to do?

I guess I'll have to tell unraid to resynch parity after that.

 

Regards,

   myce

You outlined the steps exactly.    You'll not have to tell unRAID to re-sync as pressing the button labeled as "restore" will immediately invalidate your parity data.  It will automatically start a new parity calculation when you next start the array.

 

Joe L.

Thanks.

 

Am I right that the procedure would be different if I had already updated to 4.7? I seem to recall reading something about the Restore button being removed and a shell script (initconfig or something along the line) took it's place.

 

myce

Thanks.

 

Am I right that the procedure would be different if I had already updated to 4.7? I seem to recall reading something about the Restore button being removed and a shell script (initconfig or something along the line) took it's place.

 

myce

Correct.  And in the 5.0beta4 there is now a "New Config" utility screen to perform the same step of setting a new configuration. 

 

It says:

This is a utility to reset the array disk configuration so that all disks appear as "New" disks, as if it were a fresh new server.

This is useful when you have added or removed multiple drives and wish to rebuild parity based on the new configuration.

DO NOT USE THIS UTILITY THINKING IT WILL REBUILD A FAILED DRIVE - it will have the opposite effect of making it impossible to rebuild an existing failed drive - you have been warned!