[starman]

Hi all,
Been a LONG time since my last post here. Been busy. Anyway, I bought a 3TB Seagate Thunderbolt drive/adapter combo 40 days ago. Last night, all the drives disconnected from my iMac and the controller was so hot that when I removed the Thunderbolt cable, it burned my finger. When the controller died, it corrupted the drive's MBR, and now the drive is reporting that it's 800GB, not 3TB. I tried gdisk and TestDisk, both say that there are problems, neither have obvious solutions.

gdisk says that the MBR is reporting the wrong disk size. What I can't understand is how to fix it.



I tried recovery and expert modes, nothing worked.

TestDisk tried to backup my Podcasts partition to an image.dd file, but the file was 0 bytes. It's currently running a diagnostic on the HD which looks like it's going to take several hours.

My question is this - if the MBR is reporting the wrong size, why can't these tools just write the proper disk size and be done with it? If not, how can I fix it manually? The man pages aren't as complete as I'd like, and there are very few results on a Google search. Anyone have this problem or know how to fix it? The worst case is destroying the tables and rebuilding them manually (I have the partition data saved)

[reader50]

I'd pull the data from your TM backup and just reformat the 3TB drive. Detail-fixing the drive could prove time-consuming.

No TM backups? I admire your courage.

On HFS+, I've recovered drives like that a couple times. By reformatting (no zeroing of drive contents!) and resetting partitions EXACTLY as before. Then using data recovery to scan the partition(s). No idea if this would work on MBR drives, and you'd need a recovery utility that works on whatever volume formats you're using.

[starman]

The drive *was* my TM backup

I didn't expect it to die 40 days after buying it. Now I'm considering TM and cloud backup.

EDIT: I was considering doing what you said - wiping the info and rebuilding the data manually. Even though the partition table will be ok, I'm not convinced the directory structures will stay intact.

[reader50]

Whew, that's a relief. We get so many people who do not believe in backups. Their faith will keep their drive from crashing.

It sounds like you don't need to recover data, just get the drive to remember it's 3TB. Have you tried repartitioning in Disk Utility? If that recovers the proper size, you could then redo it to MBR.

If the drive hardware is reporting 800 GB to Disk Utility, then the drive firmware may be damaged. The hardware should report the proper size regardless of what the partition table says. Bad hardware info would mean an RMA to the manufacturer or store.

[starman]

Crap, I didn't think that the firmware could be shot.

The reason I need some data off the drive is because it held the raw podcast files I had. It's not crucial I get the data back, but it'll save me time in recreating some podcast-related sounds and music I made.

DiskUtility does report the drive as being 800GB, but that it has to be initialized (obviously). DiskWarrior doesn't recognize it at all, whereas it did recognize and fixed a drive that failed on me a year ago.

This is only the third drive that's ever failed on me since I bought my first drive in '87. Thankfully, the data that's on that drive is either backed up, or can be recreated, it's just that some of it is a pain to recreate.

I'll probably RMA the drive if I can't fix it.

Thanks.

[reader50]

If your podcast partition was within the first 800 GB, my rebuild method may be worth a shot. Under HFS+, that wipes the root directory and bitmap. HFS still has enough redundant file and directory data for recovery utilities to work, assuming the partition boundary begins at *exactly* the same spot as before.

I don't know if MBR / ... NTFS? preserves enough data after a fresh partition.

Data Rescue can recover even better (no reformat first), if you can tell it the starting byte of the partition you're looking to recover.

[starman]

I downloaded the trial version of Data Rescue. We'll see how that goes. 17 hours for a full scan

EDIT: I ended the deep scan early too see what it found. Seems like it was able to recover almost everything I needed. I'll pay the $100 because I think this app will at least get the data back.

[starman]

Update: Disk Rescue 3 worked like a charm for what it could see. I think that the firmware was in fact botched, and was only able to see 800GB of data.

DiskWarrior couldn't even see the drive.

I had three important partitions:

1) Media - essentially my entire iTunes library and some personal movies (kids, wedding, etc.)
2) Podcasts - all my raw GarageBand files
3) Time Machine

DR3 was able to see all of Media, but Podcasts and Time Machine were not seen due to the fact that nothing could see past the 800GB barrier.

So, it's currently backing up all the files to another drive. That'll take 10h.

I learned a few things here. First, even new devices (not drives) can fail. This isn't a failed drive problem, it's a drive interface that screwed up the drive. I generally trust certain brands, but I think Seagate's off my list now because there's NO excuse for it overheating in a well-ventilated area. Second, I think the most important data should go first on the drive in case something like this happens again. Having my Media partition back is nice, but everything there is replaceable, the Podcasts partition is not. I think that's gone forever. The downside to that is sometimes I edit pieces of separate tracks from some shows and now I can only grab audio from the completed MP3s which may or may not be clean. *shrug*. Losing Time Machine gave me a heart attack, but since everything it backed up was ok, I didn't feel bad losing it (of course now I'm paranoid).

I did some research and bought the Western Digital 4TB MyBook Thunderbolt Duo. Two drives in Raid 0, and you can change it to Raid 1 or JBOD.

In the end, I'm going to store the VERY important backups in DropBox, or have some kind of cloud-based solution.

Thanks for the help.

[reader50]

You should give Time Machine the entire backup drive. While your setup will let you recover accidentally deleted files, and older file versions, it does not protect against hardware failure. You're keeping primary data on the same device as your backups.

Had you lost the entire drive, your media and podcasts would have required major money to recover. Professional recovery services are not cheap.

I'm glad you got back as much as you did. But you're lucky to have gotten anything back with that mixed setup.

[starman]

So here's an interesting postscript to the story.

Do a Google search for "Seagate 3TB 800GB"

Yeah, apparently the *ONLY* way to get 3TB out of the drive is to attach it to a Seagate drive controller. If you don't it looks like an 800GB drive.

So even if a Mac Pro accepts 3TB drives (and they do, but non-Seagate), it'll look like an 800GB drive.

In short - there may be nothing wrong with it.

*headdesk*

[starman]

You'll never believe this - I found the cause of the problem.

It was the Thunderbolt cable that came with the Seagate drive. I know this because I finally opened the WD Thunderbolt RAID drive and plugged it in, and the cable got hot immediately.

So, I went to the Apple Store and got a new cable, plugged it in, everything is back.

Here's the thing - I never would have guessed the cable could get that hot, hot enough to burn my finger without something in the controller screwing it up. So, maybe something happened inside the cable, shorting it.

So there ya go, back to normal.