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Raid 1 format recovery

SDAVE

SDAVE

macrumors 68040
Original poster
Jun 16, 2007
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Hi All, I accidentally formatted a RAID 1 mirror (2x3TB, almost full) and need to recover the data. I haven't written anything to it yet.

I did a quick format. Any help appreciated!
 
Since the data is still on the other drive, I think Disk Utility will repair the raid automatically as long as that drive remains part of the set.
 
I have 2 drives in a RAID 1 and each one is a slice.

I formatted the main partition that has both drives combined.
 

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I am not a RAID expert. RAID 0 slices the data between two drives. In your case, with two 3TB drives, you would end up with a 6TB RAID volume. RAID 1 mirrors the data between two drives. Each contains a complete copy of the data. In your case, two 3TB drives would combine to form a 3TB RAID volume. When you referred in your original post to a RAID 1 mirror, I assumed the two drives were copies of each other. If, in fact, you have a RAID 0 set, you've lost everything on the RAID volume and you must restore from backup. RAID is not a backup solution. You should have a backup solution for your RAID.
 
chabig said:
I am not a RAID expert. RAID 0 slices the data between two drives. In your case, with two 3TB drives, you would end up with a 6TB RAID volume. RAID 1 mirrors the data between two drives. Each contains a complete copy of the data. In your case, two 3TB drives would combine to form a 3TB RAID volume. When you referred in your original post to a RAID 1 mirror, I assumed the two drives were copies of each other. If, in fact, you have a RAID 0 set, you've lost everything on the RAID volume and you must restore from backup. RAID is not a backup solution. You should have a backup solution for your RAID.
Click to expand...

It is a RAID 1, aka mirrored. Should I take out one of the drives and attach it to another mac just to see if I can see the data?
 
SDAVE said:
It is a RAID 1, aka mirrored. Should I take out one of the drives and attach it to another mac just to see if I can see the data?
Click to expand...
Your data should be intact. All you need to do is add the newly formatted drive to your RAID. Here are Apple's instructions for doing that: https://support.apple.com/kb/PH5828 When you drag the new disk to your RAID, be sure to choose RAID Slice.
 
chabig said:
Your data should be intact. All you need to do is add the newly formatted drive to your RAID. Here are Apple's instructions for doing that: https://support.apple.com/kb/PH5828 When you drag the new disk to your RAID, be sure to choose RAID Slice.
Click to expand...
This isn't how mirrored RAIDs work. They are not backup. If you format the RAID volume, both disks are erased.
 
chrfr said:
This isn't how mirrored RAIDs work. They are not backup. If you format the RAID volume, both disks are erased.
Click to expand...
Good point. I interpreted the original post to mean that he formatted one disk of the pair. If he formatted the entire RAID, then yes his data is gone--time to restore from backup.
 
chabig said:
Your data should be intact. All you need to do is add the newly formatted drive to your RAID. Here are Apple's instructions for doing that: https://support.apple.com/kb/PH5828 When you drag the new disk to your RAID, be sure to choose RAID Slice.
Click to expand...

But I formatted not one of the disks (the slices), but the main partition that contains both drives. If I add a new one, it will be recovered? The data is there, but Im worried I lost it because its part of a RAID even though its not RAID 0.

chrfr said:
This isn't how mirrored RAIDs work. They are not backup. If you format the RAID volume, both disks are erased.
Click to expand...

Yes.
 
SDAVE said:
But I formatted not one of the disks (the slices), but the main partition that contains both drives. If I add a new one, it will be recovered? The data is there, but Im worried I lost it because its part of a RAID even though its not RAID 0.
Click to expand...
Your data is erased from the disks. You can do one of two things: restore from backup, or try a data recovery utility or service. You can try the standard Mac utilities, like Data Rescue, but there's no guarantee it will work.
 
chabig said:
Good point. I interpreted the original post to mean that he formatted one disk of the pair. If he formatted the entire RAID, then yes his data is gone--time to restore from backup.
Click to expand...

I don't have a backup :((((((

OH MAN IM GONNA HAVE A HEART ATTACK
 
SDAVE said:
But I formatted not one of the disks (the slices), but the main partition that contains both drives.
Click to expand...
I'm sorry. I misunderstood. I think your data is gone. Without a backup, I think your best hope is one of the very expensive data recovery services. There are apps that advertise their ability to recover files, but I have no experience with them. Search the net:

http://www.drivesaversdatarecovery.com
http://www.cleverfiles.com/partition-recovery.html
http://www.macintosh-data-recovery.com
 
Currently running Stellar Phoenix and Data Rescue.
Wish me luck guys.

I was half asleep and running Disk Utility, a word of advice, don't do that.
 
 
 
SDAVE said:
Currently running Stellar Phoenix and Data Rescue.
Wish me luck guys.

I was half asleep and running Disk Utility, a word of advice, don't do that.
Click to expand...
In a number of cases (most) SoftRAID has been able to. The support has been outstanding from day #1.

I tell people to use a 3-drive mirror, not the minimal. Pull one for "backup" / archive or off-site. SoftRAID has more features, faster background rebuilds, checks drive integrity during idle, use all drives in a mirror for reads so that helps performance during read IOs.

You can download the demo, check the guides, and DO contact support@softraid.com
 
IowaLynn said:
In a number of cases (most) SoftRAID has been able to. The support has been outstanding from day #1.

I tell people to use a 3-drive mirror, not the minimal. Pull one for "backup" / archive or off-site. SoftRAID has more features, faster background rebuilds, checks drive integrity during idle, use all drives in a mirror for reads so that helps performance during read IOs.

You can download the demo, check the guides, and DO contact support@softraid.com
Click to expand...

Im in the process of recovering from a heart attack because I just lost, 900,000 files.

HFS+ sucks. I can't even recover file structures.

I remember back in the day I recovered an NTFS partition and I was able to bring back the file structure etc.
 
chrfr said:
No, the point of RAID 1 is to protect against hardware failure.
Click to expand...

You're getting super technical here.

I am asking for help. I made a mistake. Have no offsite backup.


I was able to use some recovery apps but all the file structure is gone and file names

this is useless.
 
SDAVE said:
I was able to use some recovery apps but all the file structure is gone and file names
Click to expand...
This is typical of recovery from formatted Mac disks. You may want to contact a data recovery service like Drivesavers, but they'll likely be unable to retrieve anything but loose files either, and it will cost significant money.
 
SDAVE said:
You're getting super technical here.
Click to expand...
He's not just being technical. He's 100% correct. I posted several links that explain why RAID is not a backup. If the loss of 900,000 files doesn't sway your opinion, I don't know what will.
 
chrfr said:
This is typical of recovery from formatted Mac disks. You may want to contact a data recovery service like Drivesavers, but they'll likely be unable to retrieve anything but loose files either, and it will cost significant money.
Click to expand...

I may be lucky, I tried Data Rescue 4 using "lost files" not "deep scan" and it found all the structures. Cross my fingers. Going to run a full recovery now it will take 14 hours.

chabig said:
He's not just being technical. He's 100% correct. I posted several links that explain why RAID is not a backup. If the loss of 900,000 files doesn't sway your opinion, I don't know what will.
Click to expand...

Of course he is 100% correct. I am not arguing that at all.

This was a local drive set which I never touch. I work off a RAID 6 that's running off dell servers and there's a daily tape backup done on multiple tapes. But this was an anomaly since I made the mistake.
 
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