3TB drive corrupted showing as 801GB

[Project Alice]

HI all,
I have a 3TB that I have been using for years. Theres around 200gb space available. So just about everything I had is on that drive (yes I had back ups of certain things but no all of it). I was using the drive in my old G5 for file server use. Well the other day I decided to retire the G5 Running leopard with an Xserve (running lion as its a 2006 model) that I got off ebay, and long story short it only had one drive bay so I put my 3tb in a USB enclosure. tonight i was trying to open a movie that was on it, and it said it was corrupted. Then i figured out every file on the drive was not working, and that it was showing the capacity at 801.57 GB. I googled this problem for about an hour and figured out that this probably happened because the enclosure probably wasnt supposed to be used with a drive that big. But some forums had said if i put the drive in something that can handle a disk that large it should work again.. So i put it back in the G5, threw it in FWTDM (firewire target disk mode), and the problem remains! disk utility says "
Invalid number of allocation blocks
The volume could not be verified completely." When trying to repair or verify it. Even if I were to repartition it which I dont want to do, it is only showing it as an 801GB drive anyways. I'm at a loss here.. Any help in recovering the drive will be greatly appreciated!

 

[BLUEDOG314]

so you're saying another machine connected via target disk shows only 800GB? Does it show your files?

If you have another drive large enough to hold all the information that should be on the 3TB one, I can tell you how to use single user mode or terminal from another machine via target disk to rsync data from the drive, but it sounds like you will at the end of the day have to wipe it if its only showing 800GB. It sounds as if the partition map is corrupt or something. May even have to dd over the partition map its self after you try backing up.

First try single user mode and run fsck -fy that way.

 

[Project Alice]

so you're saying another machine connected via target disk shows only 800GB? Does it show your files?

If you have another drive large enough to hold all the information that should be on the 3TB one, I can tell you how to use single user mode or terminal from another machine via target disk to rsync data from the drive, but it sounds like you will at the end of the day have to wipe it if its only showing 800GB. It sounds as if the partition map is corrupt or something. May even have to dd over the partition map its self after you try backing up.

First try single user mode and run fsck -fy that way.

Yes, essentially im using a G5 has a temporary enclosure. And yes it shows all of my files, Finder displays a 3TB capacity. but disk utility does not. I have a PC nvidia card in this xserve so I can only see when OS X is fully booted.. So i'll try with terminal.

 

[BLUEDOG314]

I find that disk utility is often terrible at reading capacity and such when there is any kind of filesystem issues. try going into terminal and running "df -h" and see if that reports the correct capacity. Either way, from what you are describing, it sounds like your best bet is to pull the information off then nuke the drive and start fresh.

 

[Project Alice]

The only way I was able to get it to read the actual capacity was to actually boot something with the G5 instead of just having it in TDM. Luckilly I have an iBook G3 running tiger that was up to the task of TDM for the G5 to boot from..I had an old copy of diskwarrior 4 laying around.. So i used it on the G5, and it basically told me the drive failed. Its a seagate drive that I bought a couple months ago that I bought to back up my 3TB WD drive so could take it out of its enclosure (WD drives cant be used without formatting when you take them out of the enclosure they came in). So now I'm attempting to save everything disk warrior was able to recover (which wasnt all of it but its better than nothing) to the old drive which still works after 6 years. Thanks seagate :/.....

Thank you for your help, I didnt expect it to actually be a hardware issue. I'll be taking the drive back once I scavenge all I can off of it.

 

[BLUEDOG314]

Sure. Did any other programs report it failing, like Smart utility? You can also type 'diskutil info diskX' where diskX is the identifier for the drive, and this should report Smart as either verified or failing.

 

[Fishrrman]

OP:

If nothing else works, I'll offer this advice.
Do this at your own risk.

You will need data recovery software such as "DataRescue4".

First, try DR on the disk "as is".

What recovery options does it offer you?

I once had a partition on a USB drive that was corrupted past the point of no return. The partition could not be mounted. Recovery seemed unlikely.

I re-initialized the ENTIRE DRIVE to a single partition (just a quick re-initialization and I ---DID NOT--- "zero out" the data on it).

DataRescue now "saw" the entirety of the drive (even though the drive's directory showed "empty" because of the reinitialization).

It was then able to "look around" the directory, and "go right to the platters" on the drive. Because I did not zero out the data, it was "still there" out on the drive sectors. DR scavenged and found the files I needed and saved them to a "scratch drive".

Again, a "last-resort" strategy, but it worked for me when nothing else would.