PERC 6/i Raid 5 - Foreign Config

Hello from the last screen, press F2 then you can start foreign import.
Respectfully,

@DELL-Young E​ Hi and thanks for your response.

Just so I understand - if I 'Start Foreign Import' does that restore the configuration to how it was ?

I haven't yet swapped out any drives - should I do this first ?

Hello,

no, for the moment I suggest you to import the foreign configuration without swapping drives.

Thanks

@DELL-Marco B​ Thanks for your help.

Before I try this suggestion, could you perhaps explain what this will do ? I don't understand what is meant by the phrase 'Foreign Configuration' ...

From what I can see, I have two drives saying everything is OK, and one flagged as 'foreign' but I don't understand what this actually is telling me ?

Adelphi2024,

Let me see if I can help clarify the situation for you. 

A foreign configuration is when a drives raid configuration data differs from the configuration data located on the raid controller, so basically the raid layout that the controller knows isn't being accurately reflected on the drives, so that drive is flagged as having a foreign configuration present. 

So a good rule of thumb I go by is that when you see a drive listed as having a foreign configuration, if the Virtual Disk it is part of remains bootable, and the data is still accessible, then you will want to CLEAR the foreign configuration, as the controller obviously has the correct information if it is booting normally. Now on the reverse side, if the Virtual Disk is NOT booting then you would want to IMPORT the foreign, which tells the raid controller to scrap its own raid configuration data and to use (import) the configuration data from the drive, this is because again if the controllers configuration data was right it would be booting.  

Also, with a foreign configuration there would never be a need to swap the drives, you would want to start with performing one of the steps I outlined above. 

Lastly, if both the import and clear fail to resolve the issue then we may have to retag the Virtual Disk.

Retagging would be deleting the Virtual Disk, and then recreating it exactly as it previously was (raid level, stripe size, etc) and then not initialize it, as initializing would format the drives and delete the data, , but we aren't there yet.

Let me know if this helps clarify things for you, or if you have any other questions. 

@DELL-Chris H​ 

Thanks for that very helpful explanation - that has helped me understand a lot more about what I'm being told by the controller.

So I know that I had a RAID 5 system running 3 physical drives, prior to this issue. Is that what the 'Foreign Config' is actually saying ? The Foreign View page has a PD count of 3 ...

I have ordered some additional drives - as I assumed I actually had a drive failure.. but if I understand you correctly, it might just be that the controller has ended up with the wrong config somehow ? The machine was showing a BSOD when I got to it - but I didn't note the exact stop code, but it was something about the Kernel. I assumed it would just boot again, but it didn't.

I've a couple of hopefully quick extra questions :-

1) Assuming I can recover this, can I add one of the additional drives as a hot standby ? I have a spare drive bay in the machine.

2) If we have to 're tag' the VD - how would I know the stripe size etc ?

Many thanks for your excellent support !

And just so I understand fully - is the RAID config stored on the controller and every PD in the array ? So there are multiple copies of it ?

The foreign view is showing the drives in that Virtual Disk, and is identifying the foreign one to you... 

That is correct, nothing you have said so far has definitively shown that a drive has failed, just that the Virtual Disks configuration data is incorrect, somewhere. 

To answer the other questions

1) Yes you can assign one of the new drives as a hotspare, but I would get past this first. 
2) You should be able to access the raid controller BIOS and view the Virtual Disk configuration from there. 
3) The Virtual Disks raid configuration is indeed stored at the controller, as well as every drive within that specific Virtual Disk. 

@DELL-Chris H​ 

Ok - all understood so far. Before I go and hit Import Foreign Config, I just thought I would share 3 pages from the RAID controller BIOS , if you wouldn't mind giving them the once over just to make sure I'm as confident as I can be I'm taking the correct action.

This photo shows that the PD02 is in 'Rebuild' is that OK ?

This one shows a drive as 'Missing'. Is that because it doesn't know that PD02 should be in this array, but because it's RAID 5, it knows there should be at least 3 physical drives ?

Thanks again for your help. I feel so much better with some advice from someone who knows what they are dealing with.

Hello, I recommend that you check the PD status first. If the disk has a physical issue, the foreign import won’t succeed.

Respectfully,

@DELL-Young E​ what is the recommended way to check the PD status ?

Hello,

here a guide about how to run Diagnostics to check the PD status.

How to Run Hardware Diagnostics on your PowerEdge Server | Dell US

Thanks

@DELL-Marco B​ Does that apply for my machine ? I have a Precision T7400

No this is not a server but a client product. You are writing under the wrong section (PowerEdge).

For diagnostic tool in a client environment you have to use this tool

Dell 32 Bit Diagnostics Utility (Graphical User Interface version) | Driver Details | Dell US

@DELL-Marco B​ Thanks for that link. It won't work for me though in this case, because I can't boot the operating system, as the RAID is down with the OS on it.

Also, apologies if I have posted in the incorrect section. This was the section that a google search led me to when I searched for help on 'Dell RAID Foreign Config' but I hadn't spotted it only applied to servers.