New Problem, new thread so if other have similar issues they can learn too.

This seems a bit unique from other stuff I've read.

My array expand has gone bad.

I Tried to expand disk 12 from 750 to 1.5Tb

Turns out disk 7 750 is failing (i found out during expand) and won't let the disk 12 expansion complete

 

The array now thinks disk 12 needs 1.5Tb, but what I really need to do is rebuild 7.

What I'd like to do is put the original 750 drive back in slot 12 and then replace disk 7 and rebuild.

I haven't written to the array since trying to expand. So I would think my parity is still valid (it was built about 3 days before this all started)

What's the best way to go about fixing this? Is there anyway I can tell the array to re-expect a 750 at this point (Sure... now I know to backup config). I know restore would be bad as it would blow out my parity drive.

 

Essentially I want to 'trust my array' with the old 750 back in place.

 

Any Thoughts?

 

I'm trying this:

Put all drives back into original slots, including the 'foul' disk 7 and 'restore' the array as trusted. (This assumes parity is still good. . .)

I figure worse case disk 7 is bunk any way. Best case I can install a replacement disk into slot 7 and rebuild after.

I'm trying this:

Put all drives back into original slots, including the 'foul' disk 7 and 'restore' the array as trusted. (This assumes parity is still good. . .)

I figure worse case disk 7 is bunk any way. Best case I can install a replacement disk into slot 7 and rebuild after.

Do not press the button labeled "Restore" and start the array without special steps between the two actions. It will  THROW AWAY THE EXISTING PARITY and immediately start a new full parity calculation based on the existing assigned and working drives.   You WILL lose parity's knowledge of what was on disk7 unless disk7 is working properly.    If disk7 is bad, you will lose its contents, as you are forcing the array to start to rebuild parity without it,

You must follow a specific procedure to force unRAID to know that disk7 is bad and parity is good.

 

Instructions in my next post.

 

Joe L.

Here is what you can try.

 

Power down... Put the original disk12, the 750Gig disk you were trying to expand, back into the array,  move the new 1.5T disk into the slot7 position in the array.

(I'm assuming that your parity drive is already a 1.5T drive)

 

Now, we need to perform a modified "Trust my parity" procedure to force unRAID to think disk7 is bad.

 

To do this..., (read all the next steps before doing any)

Power up.   The array will not start by itself with the changed drives.  If by chance it does start, immediately stop it.

Go to the "devices" page.  Assign the new 1.5T drive to the disk7 position.  Re-assign the old 750Gig drive that was originally in slot12 to slot12.

1. Go back to the main page and press "Restore" (you will probably need to check the checkbox under it to enable it)

2. Before you do anything else, we need to tell unRAID that disk 7 is invalid and needs to be rebuilt.  To do that

log onto the system console, or log in via telnet and type:

cd

mdcmd set invalidslot 7

It should respond that the command was accepted OK as follows:

[pre]

cmdOper=set

cmdResult=ok

[/pre]

3. Once you have set the invalid slot as disk7, you can then go back to the main page of the unRAID web-interface and press "Start"

(you will probably need to check the checkbox under it)

 

Once you start the array, it should start to write to disk7, and read from all the other disks.  If you see anything else, press "Stop" as soon as you can.

 

Once it starts, even while rebuilding disk7, you should be able to browse to disk7 to see its contents. It should just rebuild disk7, exactly the same as if it had failed and was being replaced.

 

Remember... you must issue the "mdcmd set invalidslot 7" command between pressing restore and start.  Failing to do so will cause it to write to the parity drive rather than disk7... (not at all what you want in your situation)

 

If you have any questions at all, ask them before you perform these steps.  Only do this if all your other drives are working, and you are only un-assigning the old disk7 and assigning the new disk to the disk7 slot.  Do not attempt to un-assign any other drives, or assign any additional drives while doing this.  We need exactly the same drives in place as when you last calculated parity (with the exception of the disk7 you are replacing).

 

Joe L.

Thanks for taking the time Joe.

In the invalid slot trick is really good to know.

 

My procedure was similar except I went about it this way.

Returned all drives to original position.

'Restored' array but did not start.

Ran: mdcmd set invalidslot 99

to tell system to trust parity per

http://lime-technology.com/wiki/index.php?title=Make_unRAID_Trust_the_Parity_Drive%2C_Avoid_Rebuilding_Parity_Unnecessarily

(explicitly ignoring the big red warning at the top

I then said a little prayer and started the array. Green. Good.

Next I powered down the system and replaced drive 7 with 1.5

Upon boot up of the array disk 7 was blue, so I told parity to restore it.

So far, so far  Still praying

 

Lots of lessons learned here.

Just stinks because I had checked parity not 3 days prior.

Backup your config before expanding array

Unmenu with syslog tail is your friend

Joe L. is your friend

Run monthly parity checks for peace of mind

Don't write to the array until expand is completed (I didn't, but thought about it

To do: Find a way to email if errors are found.

 

I'll keep you posted on the end result.

 

The Drive has been rebuilt based on old parity calculations. I'm currently running crc checks to determine its integrity (The majority of that drive was FLAC files which have internal CRC's built into the files)