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Broken JBOD array!

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July 15, 2009 2:19:25 PM

I moved around some things in my PC today, and when I put everything back, something terrible occurred!

I have a 3-drive JBOD consisting of Seagate 1TB drives.

For SOME reason, the third is no longer recognized BY the JBOD array as part of it!

It gives me the ability to start a new array with the third drive, but no matter what I try, I can't it to recognize it as a righteous part of the 3TB JBOD.

Now, I am absolutely PANICKING about this! I have over 2TB of data on that stupid array, and the reason I didn't opt for RAID 0 was solely because I thought the JBOD would be more safe. If I lose this, I'm just going to kill myself..

SOS. HELP. SOS

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a b G Storage
July 16, 2009 3:10:45 AM

Hmmm... you tried putting the disks back the way they were right? In terms of which ports you connected to, etc.?

Also, I don't understand... JBOD simply bunches the hard disk as one logical drive right? It should be possible to recover the files from each individual disk... got a 3.5" enclosure lying around?

More details here: http://www.tomshardware.com/forum/244547-32-jbod-failur...
July 16, 2009 6:19:22 AM

r_manic said:
Hmmm... you tried putting the disks back the way they were right? In terms of which ports you connected to, etc.?

Also, I don't understand... JBOD simply bunches the hard disk as one logical drive right? It should be possible to recover the files from each individual disk... got a 3.5" enclosure lying around?

More details here: http://www.tomshardware.com/forum/244547-32-jbod-failur...


But doesn't it take one file and split it up into 3 for each of the drives?
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July 16, 2009 12:55:52 PM

That is RAID 0 = striping. you lose 1 drive, you lose everything. JBOD = just a bunch of disks.
July 16, 2009 5:03:40 PM

spinning rust said:
That is RAID 0 = striping. you lose 1 drive, you lose everything. JBOD = just a bunch of disks.


Well.. then why is JBOD considered less secure than RAID 5?

I think it's because my files are gone! It seems like everything before July has become void and cannot be accessed.

According to you, I should have been able to recover it.
July 16, 2009 6:15:31 PM

JBOD, you lose 1 disk, you lose what was on that disk(depends on what logic was programmed into the controller). RAID 5 is striping + parity, you lose 1 disk, start looking for another, FAST. go to http://www.acnc.com/raid.html to understand some fundamentals on RAID. if your drive really isn't bad, stick it in an exernal enclosure like r_manic suggests. you might still be able to recover whatever data is on there. most of the RAID controlls i work with don't even give the option for JBOD. there is no security against loss of data. you would be better servered just presenting your 3 drives as individual drives to your OS. real RAID solutions give you security against data loss at the server level, but we still back up the data to tape (or some other solution).
July 16, 2009 6:30:17 PM

spinning rust said:
JBOD, you lose 1 disk, you lose what was on that disk(depends on what logic was programmed into the controller). RAID 5 is striping + parity, you lose 1 disk, start looking for another, FAST. go to http://www.acnc.com/raid.html to understand some fundamentals on RAID. if your drive really isn't bad, stick it in an exernal enclosure like r_manic suggests. you might still be able to recover whatever data is on there. most of the RAID controlls i work with don't even give the option for JBOD. there is no security against loss of data. you would be better servered just presenting your 3 drives as individual drives to your OS. real RAID solutions give you security against data loss at the server level, but we still back up the data to tape (or some other solution).


Okay, let me get this straight.

JBOD means that if I "lose" one disk, which I assume means that one dies, I lose whatever was on that disk only.

RAID 5 means that if I get another identical live disk, I can get everything back.

But, what about my situation where one disk is still alive but for some unfathomable reason broke from the pack?

And what the heck does an external enclosure have to do with this in ANY way? It's pissing me off trying to make the connection and I'm already thinking of shooting myself.
July 17, 2009 1:59:12 AM

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

something like this. back when i worked desktop support, if the os got corrupted but we still needed to recover data, stick the HDD in something like this then plug the USB into a computer that is working(you may have to give the drive another letter in disk manager).

RAID 5 is the most common for file storage and is very popular. it has increased read but write takes a hit (unless you have a MASSIVE array). it wll stipe the data across 2 drives and write a parity on the third. if any drive is lost, you will either:
1) have the data
2) have part of the data and the parity to reconstruct the lost data

sorry about the disk in your JBOD, i really don't use this setting, i work with servers and the stupid SAN at my work place all day. RAID can be daunting at first.

too many times i heard grad students in college say, "what do you mean, this floppy is no good?!? i have my entire thesis on it! no, i don't have it saved anywhere else."
July 17, 2009 7:53:34 AM

I've been told that RAID 5 on an nVidia nForce chipset is a "dead end." And that I should install Windows Server 2008 instead and perform Software RAID.

It's neither that my OS is corrupted or that my drive is dead.
It's that the HW RAID screwed up and couldn't detect my drive as part of the JBOD. I surmise that if I go RAID 5, this issue won't occur, but what about when I buy a whole new PC at the end of the year? How can I move the RAID there?
July 17, 2009 1:04:51 PM

Just for laughs have you tried replacing the cable on the drive that is not working?
a c 127 G Storage
July 17, 2009 9:46:40 PM

Quote:

JBOD means that if I "lose" one disk, which I assume means that one dies, I lose whatever was on that disk only.

Yes but filesystems may not like gaps in their logical space, and the space "lost" may include important meta-data that will make recovery of your other files troublesome/impossible without the missing data. A COW-filesystem like ZFS would do best with JBODs, as it stores all meta-data on ALL disks.

Anyway, if you really need the data i can restore it for you using some BSD recovery method on a JBOD. That will work, but only if the data on the disks is undamaged. Trying yourself may be easier though, just don't screw things up or you might loose all data. :) 
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