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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 3:19 am 
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I have a hard drive that has a SMART status of failing. What is the best way to try to back up everything from it? Finder copies are taking forever, 5 hours for <10GB. Should I give CCC or SuperDuper a shot?
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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 4:37 am 
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If the hd is still operating normally, I'd try to back up just your files
since apps are easy to reinstall. Last time I tried CCC it seemed to
take forever to clone a drive, but that iirc was including apps.
I haven't tried SuperDuper but have heard good things about it.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:10 am 
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If its failing, go for important files first. forget apps, the os, etc.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:15 am 
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Exactly. Cherry pick only that which is vital. Don't bother backing up anything that is replaceable. Time is of the essence.
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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:35 am 
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It's all music and movies, all replaceable but at the cost of time, effort and money. The other problem is that when OS X hits an unreadable file, it stops the whole copying queue, so I have to figure out what successfully copied, then try to copy the rest. Is there anything that will run a copy job and just report errors at the end?
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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 6:51 am 
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cancerman wrote:
It's all music and movies, all replaceable but at the cost of time, effort and money. The other problem is that when OS X hits an unreadable file, it stops the whole copying queue, so I have to figure out what successfully copied, then try to copy the rest. Is there anything that will run a copy job and just report errors at the end?


The Finder still copies things alphanumerically and hierarchally. So it copies the stuff in applications from a to z before it starts copying every folder in developer a to z. It copies a to z in System long before it gets to the Users folder, etc.. So when you run into trouble the last file in existence alphanumerically is the one it was choked up on. You can verify this with getting info and just comparing sizes between recovered files and originals. In the case of bad blocks or other serious disk error you usually have to write that last file that wouldn’t copy off. I don't know a better way to do a batch copy for recovery. The finder way takes a long time but lets you know what's gone bad.

Sometimes when a disk is dying diskwarrior helps alot. You let it do its thing up to the preview and then have a much better/easier time copying from the preview. It doesn't always work (this technique let me down recovering from a 200GB Maxtor recently) and as others have said time is of the essence.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 7:20 am 
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Data RescueX...
http://www.prosofteng.com/products/data_rescue.php

Tri-Backup...
http://www.tri-edre.com/english/tribackup.html

30 day free trial.

Also, Disk Utility seems to img a failing drive, of which then Data Rescuex can get the files from, even if the img won't mount or Restore.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 10:50 am 
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If you have another large disk available, and you're patient, you can get a copy of the disk minus any bad bits by making a clone of the disk using dd, which is capable of ignoring unreadable portions of the disk -- although it can take it a long time to give up on those portions that can't be read.

To do so, open terminal and type the command: Code:
Code:
diskutil list

and locate the device number of the disk. It'll be something like /dev/disk1.

Then unmount the drive by dragging it to the eject icon in the dock, clicking its eject icon in a Finder window, or unmounting it from Disk Utility. Then issue the following command to make an image of it on another drive, substituting "/dev/disk3" for whatever device you identified in the first step, and substituting "/Volumes/My\ Big\ Drive/backup.dmg" with a path to the disk image file you'd like to create (don't forget to put backslashes in front of spaces): Code:
Code:
sudo dd if=/dev/disk# of=/Volumes/My\ Big\ Drive/backup.dmg conv=noerror bs=16384


The command works as follows:
dd is the name of the command to duplicate the disk, bit-for-bit.
if=/dev/disk# is the parameter telling dd where it should read data
of=/Volumes/My\ Big\ Drive/backup.dmg is the parameter telling dd where to put the output.
conv=noerror tells dd that if errors are encountered to pad the unreadable portions with null bytes and keep going. NOTE: I don't know if it pads the entire I/O block, or just the unreadable bits, or the hardware block, which leads us to...
bs=16384 which tells dd to use a block size of 16384 bytes. This is a lot faster than copying in 512 byte chunks, which is the default as well as the hardware block size, but I don't know how it will interact with errors. For efficiency, keep this an integer multiple of 512.

When the drive encounters bad sectors it won't give up easily. If there are lots of bad sectors, this means it may take a very long time to get past them. You also won't see any indication of progress in the terminal, except for when bad blocks are encountered and dd spits up an error notification, but you can see the output file size growing by doing Get Info in the Finder.

Once you're done, you can double-click the dmg file to mount it and copy the files anywhere you want. Good luck...

- Anonymous

Last edited by -anonymous on Sun Jun 03, 2007 2:53 pm; edited 1 time in total


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 10:52 am 
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I can stand by Data Rescue as having been my best chance at making a grab for data (we use it in our shop regularly for data recovery). Once it scavenges the directory, you can select whatever files you want to pull from the drive. If I suspect that the drive is really going to go down hard, I won't even bother trying to clone.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 11:29 am 
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Disk Utility image failed. I'll get Data Rescue tomorrow. Now trying the terminal image command, will report progress. Thanks for all the input everyone.
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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:15 pm 
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I had my external 250GB drive die a couple months ago. Most of my important data was backed up to other places, but a lot of the less important stuff wasn't... bad monkey.

Because the directory was trashed, and it was a hardware failure and not just corruption, I ended up using DiskWarrior to build a read-only copy of the partition, then slowly moved items over to blank space on another drive. It was really slow going, I ended up having to go into folders and even subfolders of folders to copy items since the copies would error out and fail when they hit a bad spot, but after a while I hit upon an amazing fact - if I interleaved several copies, almost none of the copies failed. Data that was previously erroring out suddenly was available and copied over.

All told I lost about 30GB, and I ended up recovering about 190GB.


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:45 pm 
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my recommendation is filesalvage.

http://www.subrosasoft.com/OSXSoftware/index.php?main_page=product_info&products_id=1

i used it successfully to recover email, word, excel, and ppt files from a drive that wouldnt boot (through firewire target disk mode). fiwi target disk mode is handy since you dont have to take the drive out, provided you have 2 macs with firewire.

this drive was bad i tried everything on it, norton, disk utility, data rescue, disk warrior. filesalvage was the only thing that was able to recover everything, even deleted files from years past. its is fine tunable so you can have it skip files that you are not interested in and search empty parts of the disk.

just my 2 cents in case things get real bad


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 Post subject: Backing up a failing HD
PostPosted: Sun Jun 03, 2007 5:52 pm 
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Data recovery programs are good for partition or file problems, but in my experience, the best way to save files from a hard drive that's about to die is to just copy what you can in Finder or Terminal. Recovery programs cause a lot of disk activity (other than actual copying), that can sometimes make the drive fail even sooner. As 8600 mentioned, Finder copies files alphabetically, so I normally start with important folders like Documents, then if it fails half way through, I can just have two windows side by side to see where the file transfer failed, and continue from there.
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 Post subject: Backing up a failing HD
PostPosted: Mon Jun 04, 2007 6:42 am 
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If copying the essential files fails one other non destructive thing you can do is run SpinRite on the drive. You would need a PC box you could temporarily connect the failing drive onto because SpinRite runs only in DOS - it actually can boot and run from a floppy. It will repair a Mac OS formatted HD just fine since it is just looking at the hardware at a very very low level and works by moving data that is barely readable to sectors that are proven reliable. SpinRite is from Steve Gibson's company (www.GRC.com - the Shields Up website).


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 Post subject: Backing up a failing HD
PostPosted: Mon Jun 04, 2007 8:01 am 
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Well, anon's method created a 111GB disk image on a tertiary HD. It took about 12 hours. I haven't checked it yet, but hopefully most of the media I wanted made it over. Strangely, the terminal never gave me any errors, but the image is 20GB less than the amount of data on the drive. One of the more important things on there is my gf's music library. Hopefully most of her music is not among the missing files.

Luckily this was just a second drive holding media. Even more luckily (?), this is not my primary machine.

DW and other programs to repair the drive probably would only hurt since it the SMART status that indicates it's failing. It probably some internal physical malfunction, not just bad blocks or directory corruption.
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 Post subject: Backing up a failing HD
PostPosted: Mon Jun 04, 2007 10:15 am 
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SMART doesn't know about your directory; it only indicates physical problems, although this could be bad blocks.

The size discrepancy may be due to the way size is calculated. Hard drive manufacturers usually calculate size such that 1GB = 1 billion bytes, but other computer things would measure it as a power of 2, so that 2^30 = 1.07 billion bytes. If you had a drive advertised as 120GB, that'll be 120 billion bytes, which is less than 120 * 2^30. The practical upshot is that a drive sold as 120 GB will appear as roughly 111 GB due to the different definitions of a GB.

Please let us know if the dd worked! You should be able to mount the disk image by double-clicking it, then drag any of the files to copy them just like you would from any other disk. If there is directory damage on the image you may be able to fix it with a disk utility. Similarly, you may be able to recover lost files with a disk utility, thanks to this being a bit-for-bit image of the original drive.

If it took 12 hours then there were definitely some places the machine had trouble reading the original drive. It should normally take about 3 hours to duplicate an entire 120GB drive with bs set to 16384 (smaller block size will dramatically increase the time needed). Since it had trouble, it may have filled in null bytes in some of your files. Thus don't assume that just because you can copy a file off the image that the file will work correctly. On the other hand, you probably couldn't have done any better by any other method -- at least without specialized equipment.

- Anonymous


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 Post subject: Backing up a failing HD
PostPosted: Mon Jun 04, 2007 10:48 am 
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FWIW, I have an 80GB drive that first failed SMART over 1.5 years ago. The drive is still going fine. I don't trust it as far as I can throw it, it's down to solely being a target disk for CCC before I apply an OS update, and I make sure to boot off the disk prior to messing with the original just in case this CCC was "the" copy that killed it, but... damn thing just keeps on working.

Obviously if you've got a problem copying data off the disk then that's a whole other ballgame. That 250GB disk I mentioned never once complained about SMART, even when I directly cabled it to a PC for scrubbing prior to shipping it off for warranty replacement.

Basically SMART isn't the be-all end-all of drive failure - in theory if SMART gets tripped then the drive is supposed to be heading on the road to failure. In practice though...


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