Data Rescue II AND Disksaver for failing hard drive?

Question

I need some guidance on rescuing data from an internal hard drive that Disk Utility could not fix. (The drive is making an odd noise, and apparently has a mechanical problem.)
Data Rescue II appears to successfully cloned my iMac's drive, while Carbon Copy Cloner and SuperDuper froze when I attempted to use them on it.
I just finished my cloning of the problem drive with Data Rescue II last night, and I'm debating my next step. I bought Diskwarrior as well, but haven't opened the box yet.
Should I now use Diskwarrior to build a new directory for the clone, or is that new directory generated by the Data Rescue cloning? Also, can you boot from the clone created by Data Rescue II?
I'm thinking of having a replacement drive installed in my iMac, then cloning back to it from the clone I made last night, if it's healthy. Any thoughts?

Answer 1

Gary,
Always interested in drive failures (and trying to avoid 'em!)
Saw a link on StorageReview to a study done by Google:
Predicting hard drive failures
Its a study by some Google employees on the failure rates of disk drives deployed within their infrastructure.
Failure Trends In A Large Disk Drive Population
Examining the population of hard drives under deployment within Google
* In general, there are around four ways a HDD will fail. Firmware zone corruption, electronic failure, mechanical failure, and logical corruption. Unfortunately, S.M.A.R.T only handles a subset of the "mechanical failure" category (mainly media failure and thermal failure), and does not protect against single instance/incident catastrophic mechanical errors (head crash, spindle/servo motor failure, stick-shun).
* I was surprised about the lack of correlation found between elevated temperature and expected drive reliability. The graph only went up to 50 C, though, and I would expect a much stronger correlation once the temperature reached beyond typical max temp specs.
* I give props to the google crew for their SMART correlation analysis. I would have loved to see a quick postmortem on all of the failed drives to determine cause, and a breakdown into the top four categories.
* Side note, logical corruption may lead to data loss, but it does not necessarily mean that the HDD has failed.
Findings:
* After a first scan error, drives are 39x more likely to fail within 60 days.
First errors in reallocations, offline reallocations, and prob ational counts are also strongly correlated to higher failure probabilities.
* A large fraction of our failed drives have shown NO SMART error signals watsoever.
* There was a lack of a consistent pattern of higher failure rates for higher temperature drives for for those drives at higher utilization levels.
* Some of the charts point to drive failure early on, a "survival of the fittest" perhaps.
http://labs.google.com/papers/disk_failures.pdf
SMART is not that reliable at predicting, of course if it shows a problem, it is just that much worse. I try to torture and kill a drive right off the bad, if it survives the first week of abuse, it is probably going to survive anyway. But being paranoid, never leave data to chance, assume that it will some day fail or at least need to be reformatted or retired.
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