On Dec 27, 2011, at 8:16 PM, Nathan Sims wrote:

> 
> It's still running, chugging out message after message, so it looks like Disk 
> Warrior is it telling me that the drive is toast. It does say "Speed reduced 
> by disk malfunction." I hate to lose a year's worth of backups... 

Chances are they are already toast. jhfs+ is very unforgiving of Time Machine 
backups if directory data is compromised. The journal is not checksummed, and 
it only applies to filesystem metadata anyway, not data. I've consistently 
found Time Machine backups that have become corrupt to restore corrupt.

However, while as a whole it is likely toast, it is unlikely it is worthless in 
pieces. In this case the parts are worth more than the sum. Do a sector copy to 
an ISO ASAP.

sudo diskutil unmount /dev/disk1sX
dd if=/dev/disk1sX of=/Volumes/Newdisk/TMbackup.iso bs=1m

You can even point Time Machine to this (mounted) ISO for restore, but best to 
go digging in for individual files, and checking to make sure they are valid.

If you care about the data, I wouldn't futz with anything else, not even a 
repair. You can do a repairs or try to make a better second ISO later. If the 
drive is dying and you care about the data, it doesn't matter the state of the 
directory is in when taking the first imaging. It's either fakaked beyond 
repair or not.



> Only a year old! I just checked out Seagate drives online, and they like WD 
> have only a 1-year warranty. Wow, whatever happened to the industry-wide 
> 5-year warranties on these things?
> 

Part A is Thailand floods. Part B is they are taking liability off their books 
sooner. Part C is they are taking part of that liability and turning it into 
insurance income through optional extended warranties. But it's somewhat rare 
to see a drive die at 1 year, I think. The profile is bathtub curve, failures 
early, failures near end of service life. But Time Machine is pretty intensive 
on how many tiny files it creates, mostly hard links. So it's getting a work 
out every single hour of its 1 year life. Plausible...

Anyway, look at your credit card. It might have an extended warranty. Amex will 
double the manufacturer warranty. It's less common with consumer Visa 
MasterCard, but some business Visa MasterCard will also have some extended 
warranty.

5 year warranties are primarily the domain of SCSI/SAS enterprise drives.

If you're curious, smartmontools can be useful to extract substantial details 
from the drive. It's not easy finding a binary package. I happen to have 
PowerPC, Intel 32-bit and Intel 64-bit installers, built with MacPorts. I find 
it an abomination that Apple doesn't include it in client. They do in server. 
There's no good reason to not have it even if most users won't customize it to 
track key values indicating old age. Only when serious problems are occurring 
for a sustained amount of time, in one of a handful of pre-fail categories, 
will the drive itself propose it's about to die. The self-health assessment of 
SMART predicts failures less than 50% of the time, the only real way to know 
this in advance is tracking rate of change with regular extended tests with a 
custom smartd script.


Chris Murphy
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