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forgot to remove failing drive after hot spare

I used configuration utility to turn a failing drive offline and thus rebuilt the hot spare to replace the failing drive member of RAID 5 (3 disk) array.  The drive rebuilt overnight and in the morning the server was rebooted without removing the failing drive.  Now the failing drive (Error on SMART state) is in the status of "REPLACING" at about 50%.  I assume it is now replacing the drive that I just replaced it with!  Obviously I don't want this.  Is there any way I can stop this before it completes? It it completes will I have to go thru the whole process of replacing it with the drive I replaced it with before? 


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Re: forgot to remove failing drive after hot spare


It sounds like the copyback feature. If copyback is enabled then when the system detects a valid member for the virtual disk in the slot of the previously failed disk it will initiate a copy from the hot spare. The copy is not the same as a rebuild, it should be much faster than a rebuild because it is a straight disk-to-disk copy instead of a virtual disk rebuild. After the copyback finishes the hot-spare should go back to a hot-spare status.

The copyback has likely completed by now. You would need to check the manual to see if it can be interrupted. Pulling the disk would interrupt the process, it should cause the hot-spare to remain as a member since the changeover back to hot-spare does not occur until the copy finishes.

If you want to replace the disk then yes, you will go through the same process again. This is what I would do to limit the number of rebuilds.

0 - online
1 - online
2 - online
3 - hot-spare

Your configuration should be similar to this right now. Let's say you wanted to replace disk 1. If you pull disk one a rebuild to the hot-spare will initiate automatically. I would remove the hot-spare status from PD3. This will stop it from rebuilding. You can then offline and replace disk 1. The rebuild should start automatically on the replacement disk. You can then set PD3 back to hot-spare. This will allow you to skip a step and avoid an unnecessary rebuild onto the hot-spare.


Daniel Mysinger
Dell EMC, Enterprise Engineer

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