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Yesterday one of the three Raid 5 disks I have configured into my DELL Server PERC H310 controller cannot be found anymore.

I cannot replace the faulty driver now, so the thing I actually would like to do is to turn it into a RAID 0 for the time being.

Is it possible to do this without loss of data? If yes, how?

Thank you so much.


As said in the comments, I think what happened is that previously one of the three drives died. Then a second got foreign to some error (and now my data is not exposed).

The question is: What happens if I import the configuration of the foreign disk? Will it get together with the one that is ready and expose the data for me, so that I can get them back?

Thanks a lot!

3 Answers 3

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So you have a redundant array of disks that started to die. And you want to migrate it to the raid level where the death of a single disk will be fatal for data.

My opinion - it's some sort of complicated suicide.

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  • Thanks for the input. My idea of course is to reacreate a brand new RAID 5 array with 3 other disks.
    – Scudelari
    Feb 18, 2015 at 12:40
  • I would have it migrated to raid 0 simply for the sake of rendering the data available again for one week and then move all the data to this new array.
    – Scudelari
    Feb 18, 2015 at 12:41
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Though it's feasible that this could be done simply based on the math (no change in usable capacity, essentially convert all of the pieces of parity data stored on the drives into "normal" data), I seriously doubt that the H310 will support RAID level changes while the RAID set is not in a healthy state.

Why would you even want to do this? Simply to make the blinking lights all be green again? Attempting to change the RAID level while degraded would put a heavy workload on the two remaining drives, and greatly increase your risk of an additional drive failure, which would bring things down completely.

I'd recommend you do what you need to in order to obtain a replacement disk. In the mean time, if you don't have a backup of the data, you should get one immediately... and hopefully it won't be too late. Until you have a replacement drive in hand to rebuild to, you should leave the RAID5 in a degraded state.

Now if I'm wrong about your reasoning and you want to stick w/ just 2 drives for the long term... You should probably just get a full validated backup, recreate a new RAID0, and restore data to the new RAID... and keep regular backups going for when the RAID0 eventually fails on you.

Addition after your edit: That clarifies things greatly... So the general rule-of-thumb for foreign configurations is that if the foreign state is on multiple drives and causes the RAID to be shown as offline, then you import. If it's on a single drive and the RAID is still "alive", you simply clear the foreign config and rebuild. In your situation, an import might get things back up, or it might still leave you with a failed RAID... or the import may just fail altogether. If you have a backup to restore from, I'd go ahead and try an import. If that doesn't get the data accessible, then just delete the RAID, create a new one, and restore from backup.

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  • The thing is, the data is not exposed. I am not on the site, so I don't know all the information. But what I do know is that from the 3 disks, only one is shown as available. One is shown as foreign and the other one has gone on vacations.
    – Scudelari
    Feb 18, 2015 at 12:43
  • I am not a RAID expert., to be honest. But what I think happened is: One disk died and the other two were still working just by themselves.
    – Scudelari
    Feb 18, 2015 at 12:44
  • Then the second disk got due to some weird mistake.
    – Scudelari
    Feb 18, 2015 at 12:45
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Just experimented the same thing with no answers to be found in internet. I had a 4-disk Raid5 with one disk failed. So I wanted to replace the disk. I have the PercH310 in my heavily modified T3600 case so to determine, which disk actually failed I made the mistake and unattached two of them. I taught that when I put the working one back then It'll work agan. But it showed up foreign. After almost crying (yes I'm a grown man but this array had 5tb of all my stuff, cinsisting mostly of my whole life full of videos and pictures. After hors of reading up it turns out that when you were not rebuilding some of your disks at the moment of pulling the drive, you should import. As the drive got removed, its now considered 'foreign' just for safety and not included back in the array before you import it. Finding the inporting location is another problem. I found it under VD Mgmt tab. While I sat my cursor on my controller (PERC H310) row I pressed F2 and it gave me the 'import' and 'clear' option. From there, irs pretty straight forward. Good luck!

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