Anyone tried to reconstruct a RAID 0 to a RAID 5?

Posted on 2008-02-04
Medium Priority
Last Modified: 2013-12-01
I have an issue with one of my servers.  One of the HDD in a RAID 5 has failed.  And in my desperation without paying much attention, I began a reconstruction of the RAID 5 to RAID 0.  Has anyone had any luck in letting the reconstruction complete and then reconstruct it back to a RAID 5?

The reconstruction is going very, very slow and I would hate to abort it, in fact, I cannot even abort it.

The LSI Logic MegaRAID SATA 300-8x  Adapter will not allow me to abort the reconstruction process now.

I am willing to give anyone points just for giving me their advice on my situation.

Thank you for your time.

Question by:dgriffit55

Expert Comment

ID: 20818710
The reconstruct is a process you will typically not want to stop.  If the changes are halted in mid-progess, they may not back out gracefully.  The issue you are going to have is the array size.  You were losing a disk worth of space for parity in the raid 5.  By reconstructing, the array will now be larger because you no longer have to account for parity.  Reconstructs will typically only let you go to the same size or larger.  I believe to go back to a raid 5, you will need to add another disk so that the overall array size will be equal to the size of the new array after the reconstruct or you will have to delete the array and recreate it.

Author Comment

ID: 20824858
I actually, accidentally moved one of the 5 drives out of the RAID 5 array into a RAID 0 array.  So, now I have 4 250GB SATA drives in a RAID 5 array still and the funny thing is the other RAID 5 array with the 5 250GB SATA drives and Hot Spare 250GB SATA drive is only about 20GB bigger.  However, I would like to look at reconstructing the other 250GB SATA drive and Hot Spare 250GB SATA drive back into the first RAID 5 array down the road.  Do you think this is possible?

Thanks again for your help.


Accepted Solution

_Mr_Limo earned 1500 total points
ID: 20825550
I'd shut it down now, if you want any chance at getting the data back - it may already be a lost cause, but if it completes it WILL be.  

Call DriveSavers Data Recovery www.drivesavers.com & they'll take care of you.  NOt cheap, but the best in the business.

If your data is not important, let the process finish & then rebuild as you want it to...

With regards to your question about the capacities, 4x250 GB drives in a RAID 5 gives you accessible space of around 750GB.  5x250 GB in a RAID 5 where one of the drives is a hotswap spare is essentially the same - 750GB of accessible space and a spare drive that will kick in when one of the others fails...

If all your trying to do is get the drives back into the array, let the initialization of the array complete & then start again with the drives part of the array.

Good luck,


Author Comment

ID: 20826624
This all began because the Hot Spare didn't kick on after HDD 5 out of 6 in the RAID 5 array failed, which makes me think there may be issues with the HDD cage.

The reconstruction completed and the server seems to be working fine with one less drive in the RAID 5 array, but I will obviously make a backup and attempt to add the extra drive and the Hot Spare into the RAID 5 array by reconstructing it again.

FYI - I couldn't stop the reconstruction process.  Even rebooting the server didn't stop it.  This is one bad to the bone RAID controller.

I will let you know how it goes.

Thanks again for all your help.


Expert Comment

ID: 20849215
I think you will be able to get it back running with raid 0 i had tried this when on one of our server when one disk failed but i would advise you that next time you create raid 5 just make sure that you use hot swap as in this case if anything goes wrong with on hdd you can swap it and work it like normal instead of having pain like and and wat i had..
Let me know if you need any further info

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