OT: Salvaging data from failing hard drive

[mike]

I have a 2TB Hitachi external drive which seems like it's failing and I'm wondering about the best way to recover the maximum amount of data from it before it dies completely.

This morning, a file on the disk failed to open and the drive started making what I would describe (possibly incorrectly) as repetitive hunting noises - a repeated series of clicks as if searching.

This drive is connected to a Mac using Mountain Lion via USB, and I don't have easy access to a pc.

Ultimately the Finder had to be restarted without the drive connected.

When the external drive is first plugged in, the computer recognises it and it's possible to see the main folders on the disc. At first clicking on some of the folders shows the contents, but then the clicking starts and opening further folders doesn't reveal the contents. Sometimes, the contents of previous folders seem to disappear.

I have about half of the data backed up anyway and none of it is critical but I'd like to get a clone of the drive if I can.

I've tried dragging a few items to another drive but it never gets further than "Preparing to copy=85"

Can anyone suggest what the likely failure is and the best way to retrieve the maximum amount of data?

I'm guessing it's some kind of mechanical failure rather than the platter itself being stuffed...

[jrwalliker]

You should assume that every access might be the last, so don't waste them.= Clone the disc to a new drive of the same size or larger (or to an image = file). Use a program that doesn't initially keep retrying the bits that it= can't read, as this just wears out the disc more quickly. Instead, use on= e that concentrates on getting as much of the good stuff off first, and onl= y then nibbles away at the bad bits.

Such a (free) program is "gnu ddrescue". Although it was originally writte= n for linux, there appear to be some MAC binaries around. Don't confuse it= with dd_rescue which is similar but IMHO not as good. Mount the source dr= ive "read only" if you can.

I have found ddrescue to do a much better job than some commercial offering= s. Be prepared to wait for results. I once left ddrescue running for a co= uple of weeks to get as much off a badly corupted drive as possible.

Once you have cloned as much of the defective drive as possible, take a cop= y of the clone and use system recovery tools on that, not on your master co= py. That way you can start again if they mess it up even more.

Before starting, read the instructions. Then read them again. And again.

John

[The Natural Philosopher]

classic sign of try8ng to read an semi readbable track

so?

Mac is always a total bitch to recover from due to the use of data and resource forks.

Boot the mac with a live Linux CD and add a second USB drive, and try a console level copy.

You might be able to fsck it ...and get a bit more back

[Grimly Curmudgeon]

Put in a plastic bag in the freezer for a day. Remove, plug in and get the data off before it warms up properly. It works in a significant number of cases, but no guarantees.

[RJH]

Check first it's not the cable and, if you can, the caddy. Mine's (iMac) sniffy about cables.

Rob

[chrisj.doran%proemail.co.uk]

You might also try another wallwart (if it uses one). My external drive (albeit a different model) somehow "wears out" the warts the manufacturer supplies -- after a while they can no longer supply enough current. I now use a beefier one.

You can also get a USB cable with a box on the end that connects to various drive types, bypassing your own box's electronics/PSU in case the problem is there.

Chris

[Another John]

The MacOS has a utility called Disk Utility, which will attempt to repair damaged disks (your disk file structure may be damaged, as opposed to the hardware).

Disk Utility is in the Utilities folder, which is inside your Applications folder. Open the application, select your disk, and see what "First Aid" in Disk Utility offers you -- First Aid is the default option when you open the utility.

If Disk Utility can repair your disk, you will be able to access all files again, and then is the time to start copying them over to a new backup disk. The application is full of useful information and advice.

HTH John

[Brian Gaff]

Sometimes orientation can make them work for a bit i found, but it sounds like its a bit late to do very much if its that unreliable. I guess you would need some kind of brute force system bypassing drivers ona windows box. Brian

[Jules Richardson]

Wot he said... the only thing I'd add is that sometimes heat or cold helps, so some experimentation there might be worthwhile once you've run as many room-temp passes as you feel necessary.

cheers

Jules