[Solved] Unraid Ooops. Pulled Wrong Drive


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So I have my unraid 6.9.2 operating and it works like a charm.  I went to add a 2nd cache drive to unraid and when I did, I accidently pulled the wrong drive out of my Hot Swap server.  I pulled my Disk 8 instead of the empty tray (i'll calll it "Slot 9").  I immediately reinserted the drive, stopped the array and reallocated "Disk 8" back to the proper HDD.  After doing so, I get the infamous Red X indicating the drive is being emulated.    How does one fix this?  Does running a parity check solve the problem?  I know there's nothing wrong with the drive or the data on the drive -- i just pulled the wrong one while being a dummy.  Happy to post diagnostics if necessary but I wasn't sure it was required because I know exactly what the issue is.

 

Thanks for your help!!

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6 minutes ago, trurl said:

Solved -- thanks for yoru help.  Was hoping there was an easy fix without having to complete rebuild but understand so.  Luckily it's only a 4TB drive so shouldn't be too bad.  

 

Actually that brings up another question.  Currently my server is operating in a 1U-4bay chassis and I have a Dell MD1200 supplementing it.  I am using all 4 drives of the 4U and 4 or 5 drives in the Storage Array.  I am upgrading from the 1U to a 3U with 16-bays.  I am simply swapping the mobo and drives over from the 1U to the 3U.  Two of the drives in the 1U are my parity drives.  Am I going to have to do a complete rebuild of every drive?  Easy way to do this?

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As long as Unraid identifies the disks correctly it should just work. Not familiar with the hardware you have or the hardware you are going to so I don't know if anything there might identify the disks differently or not. Do all the involved controllers identify the disks by their serial number?

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36 minutes ago, trurl said:

As long as Unraid identifies the disks correctly it should just work. Not familiar with the hardware you have or the hardware you are going to so I don't know if anything there might identify the disks differently or not. Do all the involved controllers identify the disks by their serial number?

 

I honestly don't know how the current controllers work. My 1U-4 HDD bay chassis is a Supermicro CSE-813M,  They are connected direct to motherboard via SATA cables. The new chassis will be a Supermicro CSE-836.  This has 16 HDD bays and will be connected through the motherboard via a PCI-e HBA SAS card. My Dell MD1200 is connected through the same SAS card.  The motherboard is Supermicro as well.  

 

I was surprised that Unraid didn't notice the drive when I accidently pulled the wrong drive and popped it back in.  It was off for only a couple seconds (not like time matters) but seeing as the drive was emulated when Unraid "recognized" it again was kind of a concern.   Figuring out how to switch chassis, especially when it involves both of my parity disks gives me a little heartburn.  

 

IS there a way to test this prior to converting chassis?  Was the issue caused by the drive being pulled while the array was still active?  I've read several forum posts that seem to indicate that Unraid should recognize these drives; however, clearly that didnt happen in this one instance.  Any advice you have would be extremely beneficial.

 

Thanks!!

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  • ChatNoir changed the title to [Solved] Unraid Ooops. Pulled Wrong Drive
7 hours ago, Hawkins12 said:

I was surprised that Unraid didn't notice the drive when I accidently pulled the wrong drive and popped it back in.  It was off for only a couple seconds (not like time matters) but seeing as the drive was emulated when Unraid "recognized" it again was kind of a concern.   Figuring out how to switch chassis, especially when it involves both of my parity disks gives me a little heartburn.

Unfortunately, the speed of reporting on issues like these -- and the infrastructure to respond to each controller's individual responses -- is not in place right now. This isn't an unRAID thing, it's just A Thing(tm) unfortunately. Your move from motherboard-SATA to HBA-SAS *shouldn't* be all that difficult, but I can help prepare for that to at least some degree, because I've gone through it a few times, and I'm still told I have an Unapproved Setup. Frowny-face and all, I bet.

 

First and most important is to make sure you have SMART data, because with SMART data (aside from the hady thing about knowing before a drive chokes to death) we have Identification. With Identification and Preparation, things tend to go...well, less bad, haha.

 

Do you have good SMART data in the WebUI? Do you have any idea what I'm talking about? If not, pop over here for a primer on how to know what you don't know, then come back here and tell me what it is you don't know and I'll try to do what I can from there. I'm not gonna know every interface, but I'll work with you as far as I can.

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Since we don't have diagnostics (maybe I should have asked) we don't know exactly what happened when you pulled the drive. It isn't clear that Unraid didn't recognize the drive, just that it disabled the drive.

 

Unraid disables a disk when a write to it fails. This is because the disk is no longer in sync with the array. After a disk is disabled it won't be used again until rebuilt, which makes it in sync again.

 

After the disk is disabled, all subsequent access for that disk is using the "emulated disk". Any reads of that disk actually read all other disks instead and get its data from the parity calculation. And any writes to that disk, including the initial failed write, are emulated by updating parity, so all those writes can be recovered by rebuilding.

 

If you post your diagnostics we might be able to see more about your configuration and what happened.

 

The following is the "long form" of my Diagnostics request:

 

If possible before rebooting and preferably with the array started
Go to Tools - Diagnostics and attach the complete Diagnostics ZIP file to your NEXT post in this thread.

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51 minutes ago, trurl said:

Unraid disables a disk when a write to it fails.

Unraid may handle a failed read by getting the (emulated) data from the parity calculation by reading all other disks, then it will try to write that data back to the disk. So a failed read can trigger a failed write that disables the disk.

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16 hours ago, trurl said:

 

If you post your diagnostics we might be able to see more about your configuration and what happened.

 

The following is the "long form" of my Diagnostics request:

 Unfortunately, I have rebooted so I understand I lost the diagnostics.  In watching some Youtube videos, I believe the issue is related to pulling an Array drive while the Array is running.  I can understand that this creates a hiccup.  Had the array been stopped or the server shut down, I don't see how this I would have run into the same issue.  

 

20 hours ago, codefaux said:

First and most important is to make sure you have SMART data, because with SMART data (aside from the hady thing about knowing before a drive chokes to death) we have Identification. With Identification and Preparation, things tend to go...well, less bad, haha.

 

Do you have good SMART data in the WebUI? Do you have any idea what I'm talking about? If not, pop over here for a primer on how to know what you don't know, then come back here and tell me what it is you don't know and I'll try to do what I can from there. I'm not gonna know every interface, but I'll work with you as far as I can.

 

Me again from the other post :) Again thanks so much.  The only thing I know about SMART data is that there are SMART checks on the drives.  I need to read up on this to make sure all of the SMART identification is in place before upgrading server chassis.  My weekend project was to upgrade the chassis and the last thing I want to do is lose my array so I'll certainly be looking into this very soon!

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11 hours ago, Hawkins12 said:

Had the array been stopped

It wouldn't have disabled the disk because none of the disks are mounted and so won't be read or written.

 

Whether or not "hotswapping" could lead to some other problems probably depends on your hardware.

 

And in any case, absolutely no point in plugging/unplugging assigned disks under power because Unraid won't do anything with the disk until you tell it what to do with it, and you can't tell it to do anything with it while the array is started.

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