Swap-Disable


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From the Wiki page: http://lime-technology.com/wiki/index.php/Un-Official_UnRAID_Manual

Actually same instructions in the official manual as well: http://lime-technology.com/wiki/index.php/UnRAID_Manual#Replace_a_failed_disk

 

You must replace a failed disk with a disk which is as big or bigger than the original and not bigger than the parity disk. If the replacement disk is larger than your parity disk, then the system permits a special configuration change called swap-disable.

For swap-disable, you use your existing parity disk to replace the failed disk, and you install your new big disk as the parity disk:

Stop the array.

Power down the unit.

Replace the parity hard disk with a new bigger one.

Replace the failed hard disk with you old parity disk.

Power up the unit.

Start the array.

When you start the array, the system will first copy the parity information to the new parity disk, and then reconstruct the contents of the failed disk.

 

Clearly these instructions are either wrong or incomplete with detail for a swap-disable.

 

I am able to test this functionality finally. So following the wiki or official manual:

 

Stop the array. (OK)

Power down the unit. (OK)

Replace the parity hard disk with a new bigger one. (OK, added a 4TB drive to the existing slot where the previous 3TB parity drive was, not that slot position matters)

Replace the failed hard disk with you old parity disk. (OK, moved the previous 3TB parity drive into the slot of the drive I am replacing, thereby removing a 250GB Data drive that was there and was not failing)

Power up the unit. (OK)

Start the array. We need to stop here, as this would do nothing except bring up the array with a missing disk;

 

The Device Status page shows the previous 3TB party drive as still being assigned, it didnt care slots were changed, this is understood.

All that is being reported is that the 250GB Data drive is Missing (Stopped. Missing disk.). So IF you start the array as per the last step in the WIKI then

Start will disable the missing disk and then bring the array on-line. The disks data will be available, but the array will be unprotected; install a new disk as soon as possible.

 

That is not a swap-disable.

 

IF you change the parity drive assignment from the current parity drive to the new hard drive that was added to the array (In my case the 4TB drive) you instantly get a "Wrong" under the device assignment, but this now free's up the previous parity drive in order to be able to assign it to the missing data drive assignment. This too instantly displays "Wrong" is the Device Status page. And you have no option to start the array

Too many wrong and/or missing disks!

 

So that too is not a swap-disable.

 

So what step/instruction is wrong and/or missing in the official manual or Wiki in order to be able to perform a swap-disable?

 

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@Fireball3, yeah I saw that thread, a bunch of people with too much to say but yet never did it themselves.

I emailed Tom as well but no response. Another QA fail. Manual is published with incorrect steps that don't work.

 

I pity the person who will have a true drive failure and hopes to accomplish a swap-disable. Tom doesn't respond to support emails, and you'll get worthless comments in the forum that you did something wrong, where the real problem is simply it doesn't work.

 

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I got it to work.

Step 1 remove bad hdd. Unassigned from slot.

Step 2 start array.

Step 3 stop array.

Step 4 assign new drive as parity.

Step 5 assign old parity drive as old bad drive.

Copy button should appear instead of start array.

Click that button. After copy completes start array.

 

Instructions miss the point that the system needs to see that the drive is no longer available. Kind of strange but it works.

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From the Wiki page: http://lime-technology.com/wiki/index.php/Un-Official_UnRAID_Manual

Actually same instructions in the official manual as well: http://lime-technology.com/wiki/index.php/UnRAID_Manual#Replace_a_failed_disk

 

You must replace a failed disk with a disk which is as big or bigger than the original and not bigger than the parity disk. If the replacement disk is larger than your parity disk, then the system permits a special configuration change called swap-disable.

For swap-disable, you use your existing parity disk to replace the failed disk, and you install your new big disk as the parity disk:

Stop the array.

Power down the unit.

Replace the parity hard disk with a new bigger one.

Replace the failed hard disk with you old parity disk.

Power up the unit.

Start the array.

When you start the array, the system will first copy the parity information to the new parity disk, and then reconstruct the contents of the failed disk.

The instructions are correct.  The process will NOT work unless the disk being swapped is being shown as RED/disabled; in other words, a failed disk..

Clearly these instructions are either wrong or incomplete with detail for a swap-disable.

You incorrectly assumed it will work the same with a disk that had not been marked as failed by unRAID..

 

So what step/instruction is wrong and/or missing in the official manual or Wiki in order to be able to perform a swap-disable?

Actually, nothing is missing,  but it might be amended to make it more clear it is not a way to replace a working disk.

 

You can "fail a disk" by stopping the array, un-assigning it from its slot, and starting the array with it un-assigned, then stopping the array once more.. Starting the array with it un-assigned will mark it as "failed"

 

Joe L.

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Thanks, I understand now, it was not clear for me and seems for others as well that it explicitly MUST be a FAILED disk; wrong disk/missing disk are redballed as well but not FAILED.

 

Maybe Tom would consider allowing this, so one doesn't have to force a failed disk. As it seems once you take the extra steps to force unRAID to see an assignment as failed, it will perform the SWAP.

 

Months of waiting for documentation to be updated before final could be called final, and sh^ts still not clear. Tom could have answered me back with this one liner detail and the additional steps to take to achieve the same, and I am not the only one who reached out to him and got no reply. Instead I burned 24 hours with a stopped array waiting for a reply from him, and 4 days later you are the only one who can explain it properly. Wouldn't be the same if one was purchasing a license, you'd get a reply back.

 

EPIC FAILURE! Tom#2 you should get access to Tom#1 mailbox and see just how much gets unanswered so you can smack him around!

 

 

 

 

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  • 3 weeks later...

I promised to test it with the new build.

 

Now I was able to see the "copy" button.

As already mentioned above, the trick is to start the array with the failed drive.

If you don't have a failed drive you have to unassign the one you want to replace and

start the array.

Then stop the array and do the parity swap.

 

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  • 8 months later...

The fact that I am posting in this thread tells the story that today isn't a good unraid day for me.

 

The short story is that I have a disk that is showing SMART errors and some other errors in the syslog.  That discussion is in another thread, but the main thing to note is that the drive has not failed yet.  The drive that is failing is 2tb.  My parity is 3tb.  My new replacement drive is 4tb.  At the end of the day, I want the 4tb as my parity and I want to use the previous 3tb drive to replace the smaller and failing 2tb drive.  Again, this is proactive, as I have no red ball and the drive is still working.

 

At first, I thought the best way to resolve this issue would be to just manually copy using MC from one disk to another, thus moving my data off the bad drive - yes I have the extra space on other drives.  I would then just remove it from the array and later add a new drive for more space.

 

I was directed to this thread and now I am hopeful that I can get what I want without having to do the manual copy step.

 

I'd like to triple confirm the steps to do this, as I don't want to lose data.  :)  I did run a parity check yesterday, resulting in no errors.

 

Step 1 Powerdown and physically remove bad hdd. Unassigned from slot.  Don't change anything else yet.

Step 2 Power up the server and start array (I don't think it starts automatically after a failed drive).  It should show that I have a missing disk now.

Step 3 Stop array, powerdown and install new 4tb drive (will be new parity drive)

Step 4 Power up server.  Not sure if it will start the array or not.  If it does, I will Stop it and assign new 4tb drive as parity.

Step 5 Assign old parity drive as old bad drive.

Step 6  The "copy" button should appear instead of start array - Click that button. After copy completes start array.  It is not clear what the Copy button does.  What is it doing here??  Does it have to rebuild parity, or is it copy from the old parity.  Again, what is the copy button actually doing here?

Step 7  After starting the array with above steps, I should now have a new larger parity drive.  The old parity drive now should be rebuilt from the parity disk, like any other rebuild after doing a swap.  Once the rebuild of the old data drive is complete, I should be back to normal operations and where I want to be.

 

Does these steps look correct and complete?  Bottom line - what steps would you take if you have a drive showing errors and you are in the same situation as me?  I just don't want to screw up and lose data.

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Step 6  The "copy" button should appear instead of start array - Click that button. After copy completes start array.  It is not clear what the Copy button does.  What is it doing here??

 

I've never heard of a "Copy" button... on any version of unRAID I've used... (up to the 5.X series)

 

Beware... I think it just says something about copying party from the old parity disk to the new, and then proceeding with a normal recovery/re-construction to the old parity drive.

 

The process is called "Swap Disabled" and it allows you to swap the old parity with a newer larger drive and then reuse parity as the "disabled" (failed) data drive.

Seek help from lime-tech.

 

 

 

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quoting from here:

http://lime-technology.com/wiki/index.php/Un-Official_UnRAID_Manual

 

When you start the array, the system will first copy the parity information to the new parity disk, and then reconstruct the contents of the failed disk.

 

Your steps look correct.

The "copy" button will only show up if you have a red-balled drive.

That is why you have to do steps 1 + 2 (as you described).

 

It should work, but you can consult limetech and let them confirm also.

 

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  • 4 weeks later...

I decided to just upgrade my parity drive and leave the drive with the SMART errors.  It worked and after the parity drive was rebuilt, I then upgraded the bad drive.  I was chicken to try the steps in this thread.

 

By far the best choice.  There have been several instances in recent versions of UnRAID where the "swap-disable" feature has not worked as advertised.    Not sure if those were only glitches in various Betas and/or RCs, or not, but by far the safest approach is to do one step at a time, as you did.

 

 

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