Does breaking RAID1 mirror generally destroy drive contents?

  • Thread starter Thread starter ohaya
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ohaya

Hi,

I was working with an HP Proliant DL360 system with a "Smart Array 5i"
controller and 2 72GB SCSI drives.

The system was originally configured with the two drives in a RAID1
configuration, as one "Logical Drive". The Logical Drive was
partitioned as one 10GB partition and one 60GB partition.

I wanted to break the mirror, i.e., end up with 2 72GB drives, instead
of 1 72GB "Logical Drive".

To do this, I went into the Smart Array utility by pressing F8 during
bootup, and selected "Delete Logical Drive" (there were only 3 choices:
Create Logical Drive, Delete Logical Drive, and View Logical Drive).

After doing that, the system couldn't see either drive, and it wouldn't
let me (as far as I could tell) configure the drives as 2 separate
drives, so I went back and did Create Logical Drive, to put back the
mirror.

After all of that, when I looked at the drive, all the partitions were
completely gone.


I wasn't completely surprised about this, as I had been warned that this
might happen, but I thought that with a hardware RAID controller, the
two drives that are mirrored in a RAID1 configuration are still
essentially two independent drives that just happen to have the same
contents.

So, I was wondering: In general, is what I saw tonight always going to
be the case?

If I put 2 drives into a RAID1 configuration, and then later break the
mirror (in the controller configuration), will the contents of both
drives always be wiped out?

If so, why?

Does the RAID controller write some kind of configuration information
onto the mirrored drives when it mirrors the drives?

Thanks,
Jim
 
No, generally you should not lose any data. The reason RAID 1 exists is to
have a duplicate drive just in case 1 drive dies. So, if you had an array
running just fine and you turned off your computer, then removed 1 drive,
when you fired up your machine again it should work just as it always did.
The controller will just think 1 drive dies. Your array will now be in a
"degraded" state.

The drive you removed will be a perfect snapshot of your array when it was
working perfectly. If you choose to reinstall the drive, you will need to
rebuild the array. Basically, mirror the drive with the updated contents.

By deleting your logical drive, you did just that, you deleted it. The data
is likely still there, but you will need a program like Active@recovery to
get the contents back. Active @ recovery is just the one program I have
used in that situation, there are likely many many others that will work
also.

--Dan
 
dg said:
By deleting your logical drive, you did just that, you deleted it. The data
is likely still there, but you will need a program like Active@recovery to
get the contents back. Active @ recovery is just the one program I have
used in that situation, there are likely many many others that will work
also.
Click to expand...

Yes, for example DiskPatch from www.diydatarecovery.nl is also frequently
and succesfully used in similar situations (broken and re-initted RAID 0, 1
and 5 arrays).
 
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