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Strange RAID10 Recovery Order

Posted: Mon Nov 04, 2013 4:04 am
by wingsoft
Hi,
I experience a strange ( for me..) situation:

I have a RAID10 array in a PERC 6/i Controller on a Dell PE T310 server.
the order of disks in the controller is:
disk 0 : S/N 001
disk 1 : S/N 002
disk 2 : S/N 003
disk 3 : S/N 004

when I boot using the emergency console and I create a RAID10..
- If I follow the correct order of disk ( from up to down in the box ) I get NO PARTITIONS. If I perform a SCAN I get a lot of orange partitions.
- If I move the FIRST disk (S/N 001) to the second position or I remove it, suddenly appears the original 2 GREEN partitions WITHOUT a scan. Those partitions remains also if I change the order of the other disks ( disk 2, o disk 3).
In few words, I cannot move my disk S/N 002 from the FIRST position!!

Is this so strange or it's normal?

So,
I've tryed to recovery my files leaving the disk S/N 002 in the first position of the array.
It's seems that everything is fine BUT.. may files don't appear in the folders.. and when I recover, I get many YELLOW errors just like:

WARNING : Fixup 2 is ... but should be...

How can I do?

thanks a lot for your help!

Re: Strange RAID10 Recovery Order

Posted: Mon Nov 04, 2013 10:33 am
by Alt
RAID 10 means that the system writes the first identical data piece to disk 1 and 2, then the second data piece to disk 3 and 4, then to 1 and 2, then to 3 and 4, and so on. That is, disks 1 and 2, and well as disks 3 and 4, should be identical.
And it looks like disk 1 isn't identical to disk 2, and this is a problem.
Another problem is that the file system on the RAID is broken somehow, but it's impossible to say much without seeing the data firsthand.

Re: Strange RAID10 Recovery Order

Posted: Mon Nov 04, 2013 10:55 am
by wingsoft
Ok,
It's possibile that the disk 0 is totally broken.
But how can I "check" the filesystem of the raid in order to correct those filesystem error?
just like a simple scandisk do.

thanks a lot

Re: Strange RAID10 Recovery Order

Posted: Mon Nov 04, 2013 11:33 am
by Alt
wingsoft wrote:Ok,
But how can I "check" the filesystem of the raid in order to correct those filesystem error?
just like a simple scandisk do.
thanks a lot
R-Studio doesn't repair file system errors. It retrieves files from disks with damaged file systems and copies the files it finds to some other places.

For your case, I believe, the best idea is to use disks 2 and 3 (for example), and create a virtual RAID 0 from them. Then scan the RAID and recover the files.
Another important thing is that you should specify RAID parameters correctly, incorrect parameters may cause the same problems as if the file system was broken.