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Calling Dr. BOB! formatted raid

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Kevin Christopher
Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 1:16:30 pm

One of the vampires who works here formatted one of the raids last night. Luckily he stopped the moment he realized what went wrong. What is the best course of action for recovery?

Mac OSX 10.6.8
Arecca 1221X Card on a MAXX Digital EVO Box Raid 5
8 WD 1TB Black drives

He formatted it from disk utilities. Then turned everything off called me at 2:30 am and went home. So I am hopping there is not too much damage done. Well besides the fact he FORMATTED IT!

RRRRRR!,
Kevin


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Andrew Richards
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 1:45:34 pm

Try DiskWarrior and cross your fingers. If he really did just reformat the volume and immediately power down, then the data should still be there. Be prepared for the recovery attempt to take a very loooooooong time.

Best,
Andy


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Kevin Christopher
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:15:40 pm

Thats a Negative. Disk warrior can only compare the backup Directory table to the primary. When you format both are destroyed. Theoretically I could rebuild the raid, because the parity info is not destroyed, but I need some confirmation on this. Data Rescue can see the data, but it has no Idea what the file names are.

Kevin



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Steve Modica
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:29:23 pm

The raid itself was not destroyed. You don't have to rebuild that. This was a filesystem reformat (disk utility). So the RAID is happy (or should be except that he power cycled it without warning).

So the main issue is superblocks.
In the olden days, we could find a "good" superblock and run mkfs is a recovery mode pointing to that block. It would layout the filesystem again without touching the data itself. Then you could fsck or whatever.

Steve

Steve Modica
CTO, Small Tree Communications


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Kevin Christopher
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:34:09 pm

I have put my call into Disk Warrior and I am awaiting a response. I am going to wait until I can get a step by step method from somewhere. i don't want to further damage it.

Kevin



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Steve Modica
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:12:40 pm

The early superblocks that layout the filesystem geometry are probably gone. So you'll need a tool that's smart enough to search past those to later superblock backups that might still have the old HFS geometry. Then whatever data is left can be recovered.

If the inode table was completely destroyed you're not going to have much luck. If you only lost some of the root inodes (that define the root directory etc), you may end up with a bunch of files in "lost+found" that need to be recovered.

I'd consider a call with the Diskwarrior guys just to discuss whether diskwarrior can do what I described

Steve

Steve Modica
CTO, Small Tree Communications


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Matthew Mullen
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:50:29 pm

You could try Data Rescue, I've had success in the past. You will need the space to recover to.

http://www.prosofteng.com/products/data_rescue.php


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Kevin Christopher
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 2:54:09 pm

I did a preliminary test with that, but It does not recover the file names. 8 TB of QT0001.mov. Blehh!!

Kevin



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David Gagne
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 3:14:10 pm

Purchase and use R-Studio. Works well to recover raids.


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Kevin Christopher
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 4:18:52 pm

Still no magic bullet.

Kevin



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David Gagne
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 5:50:12 pm

Bummer.


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Steve Modica
Re: Calling Dr. BOB! formatted raid
on Mar 26, 2012 at 7:28:48 pm

[Kevin Christopher] "I did a preliminary test with that, but It does not recover the file names. 8 TB of QT0001.mov. Blehh!!"

I think that's the best you're going to get. If the root directories are gone, the inodes no longer have names.

Files don't really have names. They have inode numbers. Directories are lists of names that point to inode numbers. A file can have many names. It must have at least one name. You can create several hard links to the same inode (in fact, many unix commands like cp and rm are the same binary.. just linked with a different name). If you delete one of those names, the file remains (so long as there is at least one name).

You have a ton of files that no longer have names. So any utility will recover them as "generic nameX" because that's all it can do. They can look at headers and magic numbers to try and guess the type of file.

Steve

Steve Modica
CTO, Small Tree Communications


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Andrew Richards
Re: Calling Dr. BOB! formatted raid
on Mar 28, 2012 at 12:42:10 pm

I don't mean this to seem glib, because it really, really, really sucks to lose data (I have), but this is an excellent example of why RAID is not a backup.

RAID can protect you from hardware failure of HDD(s). It does not protect you from (among other risks) file system corruption, accidental deletion, or in this case, accidental reformatting of the filesystem. I know no one in this thread claimed otherwise, but for any future readers, I think the scenario witnessed in this thread can be instructive.

Best,
Andy


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Kevin Christopher
Re: Calling Dr. BOB! formatted raid
on Mar 28, 2012 at 9:54:16 pm

Yeah it sucks, but the whole thing could have been avoided if if if ...

Too many if's This really points out to me how simple the hfs file system really is. Ive always been able to recover ntfs an fat systems before. Hfs in combination with mac fork files is areal mess.

Kevin



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Andrew Richards
Re: Calling Dr. BOB! formatted raid
on Mar 30, 2012 at 8:22:16 pm

[Kevin Christopher] "This really points out to me how simple the hfs file system really is."

HFS+ is arguably the single most significant liability in OS X today. It's really a shame the effort to integrate ZFS into 10.5 and 10.6 got scuttled. ZFS is awesome!

Best,
Andy


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Matt Geier
Re: Calling Dr. BOB! formatted raid
on Apr 24, 2012 at 9:15:40 pm

Hi Kevin, Andrew and all,

Sorry to have to hear about this kind of experience. I'm also sorry to hear you may have lost critical data.

To your comment about ZFS support for Mac OS X -

There may be an option for you to consider in the future.

I don't know if anyone here has experience with it, but I'm sure this will spark some interest and we will soon find out!
I didn't see it mentioned through any of these threads here, and I looked around the COW in general but didn't find much info on it.
I felt it relevant to mention to you and others to look into.

There is a company from Colorado called Tens Complement. - http://www.tenscomplement.com

The company was founded by a former Apple filesystem and OS engineer named Don Brady. Someone who previously worked on the abandoned internal Apple project to port ZFS to Mac OS X. (I believe this internal project was closed off by Apple back in the 2009.)
-- I'm not the official word though...Only Apple knows what they are up to.

I did want to link to some interesting article reads regarding this project to bring ZFS to Mac OS X by Don Brady

(older March 2011)
http://arstechnica.com/apple/news/2011/03/how-zfs-is-slowly-making-its-way-...

(more recent Jan 31 2012)
http://www.macrumors.com/2012/01/31/zfs-comes-to-os-x-courtesy-of-apples-fo...

I did some further research and found the Tens Complements website where they are doing ZEVO (the name of the product for ZFS support on Mac OS X (Lion and Snow Leopard Supported)

You can find it here - http://tenscomplement.com/ - It seems like a very reasonable price point for a ZFS solution option with Mac OS X support.

For additional Archive and Backup -
I know LTO is still popular. You might look at the Tolis Group or one of their authorized reseller partners who offer the BRU products for Archive and Backup solutions as well. http://www.tolisgroup.com

Perhaps this will be helpful to some of those out here who come across this thread for reference.

Matt Geier
(Video Networking Solutions Expert)
(Creative Design Workflow Consultant)
(Social Media Networks Consultant)
(Technical Video Industry Sales Consultant)


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Ed Stahr
Re: Calling Dr. BOB! formatted raid
on May 2, 2012 at 5:45:49 pm

To the comment on RAID not being a backup.

After experiencing a very bad power failure (voltage crossed to the ground...) and (luckily) losing only a little data, I convinced the powers that be that we had to mirror all of our content.

Find a low cost RAID 5 solution that is of equivalent size of your editing storage. If you are low on funds, this could be a stack of software striped firewire drives, large internal drives striped, an entry level Drobo, etc. You are not as worried about speed on this. It's the safety net.

You can keep the volumes synced nightly using something at simple as Carbon Copy Cloner. If someone destroys your primary RAID, deletes a file, corrupts a project, etc. You have a nightly backup to restore from.

Just a thought and I know it does not help in your current situation, but wanted to put it out there.


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