Clearing foreign state

Question

I have a server in a remote location and one of the physical disks is showing a foreign state. Maybe it's defective or beginning to fail? I don't know. I'd like to attempt to get it back online by using the Clear function in the Foreign Configuration section. I just want to make absolutely clear that I'm not to going completely the system. lol Especially when it says that it will "remove metadata associated with the virtual disks, making the physical disk drives available for creating new virtual disks". I just want to make sure that this function is only going to affect the one, foreign disk that I'm having a problem with. I have some screenshots below. Cheers!

2020-07-24 10_00_14-KFP-SVR-01.png 2020-07-24 10_23_45-KFP-SVR-01.png

DELL-Chris H · Accepted Answer

Humphs,

A foreign drive doesn't happen due to a drive failure, but instead is caused by the Virtual Disk configuration information is different between the drive and the controllers. The controller and drives both contain information regarding the Virtual Disk configuration and one of those has changed. Now with clearing, you are telling the controller to Clear the VD config information from the drive and go with the controllers config information. Importing the foreign is doing the opposite, it is telling the controller to use the drives VD config information instead of its own. Now normally the rule of thumb is if the VD is still booting then you would clear the foreign, because if it is booting the information used is correct. If the VD isn't booting then the config data isn't correct on the controller and you would need to import the drives config information. Now with either of these it doesn't effect the data, just the configuration information. Now if these fail then you can still try retagging the VD which is deleting the VD then recreating it exactly the same without initializing the VD (which would delete the data), doing this will replace the VD configuration information on both controller and drives.

Let me know if this helps.

Humphs · Answer

Hi Chris,

Thanks for the well-thought-out reply. I will try the clear since the import doesn't change the status of the disk. I did get a flurry of alerts at the same time from the iDRAC earlier this week:

An unrecoverable disk media error occurred on Disk 0 in Backplane 1 of RAID Controller in Slot 3.
Bad block medium error is detected at block 0x46651654 on Virtual Disk 3 on RAID Controller in Slot 3.
Bad block medium error is detected at block 0x46651e52 on Virtual Disk 3 on RAID Controller in Slot 3.
Disk 14 in Backplane 1 of RAID Controller in Slot 3 is not functioning correctly.
Virtual Disk 3 on RAID Controller in Slot 3 has failed.

Does that change the course of action that I should take, short of replacing the drive? I do have a spare SAS drive that I could send out to that location.

Cheers,

Bruce

DELL-Erman O · Answer

Hello,

Since VD3 has failed and as far as I can see VD3 is RAID 0 level. I recommend you to make Chris's suggestions for Foreign drive. Because RAID 0 has no tolerance for data loss and will not be able to rebuild once a new drive installed. However, if you can access VD3 with the steps above. I recommend, you can take a backup of VD3 then you can consider using a new drive instead of disk 14. (it may have predictive failure)

Humphs · Answer

Thanks, Erman. So after running the Clear operation, the list of foreign disks was gone but the bad disk still has the caution symbol on the status and it says ready. If I go to create a new virtual disk, disk 14 is not available. Only physical disk 15. There wasn't anything important on the RAID disk. It was more of a temporary file partition to help speed up the backup program I'm using. I might send out a replacement SAS which should fix the problem. Thank you very much for your input. Much appreciated! Bruce

PowerEdge HDD/SCSI/RAID

Clearing foreign state

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