Have you first figured out the cause and type of failure ?
Here's some interesting info on types of HDD failures from Backblaze.
Reason One: Media Damage
The number one reason, accounting for
70 percent of failures, is media damage, including full head crashes.
Modern hard drives stuff multiple, ultra thin platters inside that 3.5 inch metal package. These platters spin furiously at 5400 or 7200 revolutions per minute — that’s 90 or 120 revolutions per second! The heads that read and write magnetic data on them sweep back and forth only 6.3 micrometers above the surface of those platters. That gap is about 1/12th the width of a human hair and a miracle of modern technology to be sure. As you can imagine, a system with such close tolerances is vulnerable to sudden shock, as evidenced by DriveSavers’ results.
This damage occurs when the platters receive shock, i.e. physical damage from impact to the drive itself. Platters have been known to shatter, or have damage to their surfaces, including a phenomenon called head crash, where the flying heads slam into the surface of the platters. Whatever the cause, the thin platters holding 1s and 0s can’t be read.
It takes a surprisingly small amount of force to generate a lot of shock energy to a hard drive. I’ve seen drives fail after simply tipping over when stood on end. More typically, drives are accidentally pushed off of a desktop, or dropped while being carried around.
A drive might look fine after a drop, but the damage may have been done. Due to their rigid construction, heavy weight, and how often they’re dropped on hard, unforgiving surfaces, these drops
can easily generate the equivalent of hundreds of g-forces to the delicate internals of a hard drive.
Reason Two: PCB Failure
The next largest cause is circuit board failure, accounting for
18 percent of failed drives. Printed circuit boards (PCBs), those tiny green boards seen on the underside of hard drives, can fail in the presence of moisture or static electric discharge like any other circuit board.
Reason Three: Stiction
Next up is stiction (a portmanteau of friction and sticking), which occurs when the armatures that drive those flying heads actually get stuck in place and refuse to operate, usually after a long period of disuse. DriveSavers found that stuck armatures accounted for
11 percent of hard drive failures.
It seems counterintuitive that hard drives sitting quietly in a dark drawer might actually contribute to its failure, but I’ve seen many older hard drives pulled from a drawer and popped into a drive carrier or connected to power just go
thunk. It does appear that hard drives like to be connected to power and constantly spinning and the numbers seem to bear this out.
Reason Four: Motor Failure
The last, and least common cause of hard drive failure, is hard drive motor failure, accounting for only
1 percent of failures, testament again to modern manufacturing precision and reliability.
Mitigating Hard Drive Failure Risk
So now that you’ve seen the gory numbers, here are a few recommendations to guard against the physical causes of hard drive failure.
1. Have a physical drive handling plan and follow it rigorously
If you must keep content on single hard drives in your location, make sure your team follows a few guidelines to protect against moisture, static electricity, and drops during drive handling. Keeping the drives in a dry location, storing the drives in static bags, using static discharge mats and wristbands, and putting rubber mats under areas where you’re likely to accidentally drop drives can all help.
It’s worth reviewing how you physically store drives, as well. DriveSavers tells us that the sudden impact of a heavy drawer of hard drives slamming home or yanked open quickly might possibly damage hard drives!
2. Spread failure risk across more drives and systems
Improving physical hard drive handling procedures is only a small part of a good risk-reducing strategy. You can immediately reduce the exposure of a single hard drive failure by simply
keeping a copy of that valuable content on another drive.This is a common approach for videographers moving content from cameras shooting in the field back to their editing environment. By simply copying content over from one fast drive to another, the odds of both drives failing at once are less likely. This is certainly better than keeping content on only a single drive, but definitely not a great long-term solution.
Multiple drive NAS and RAID systems reduce the impact of failing drives even further. A RAID 6 system composed of eight drives not only has much faster read and write performance than a single drive, but two of its drives can fail and still serve your files, giving you time to replace those failed drives.
Mitigating Data Corruption Risk
The Risk of Bit Flips
Beyond physical damage, there’s another threat to the files stored on hard disks: small, silent bit flip errors often called data corruption or bit rot.
Bit rot errors occur when individual bits in a stream of data in files change from one state to another (positive or negative, 0 to 1, and vice versa). These errors can happen to hard drive and flash storage systems at rest, or be introduced as a file is copied from one hard drive to another.
While hard drives automatically correct single-bit flips on the fly, larger bit flips can introduce a number of errors. This can either cause the program accessing them to halt or throw an error, or perhaps worse, lead you to think that the file with the errors is fine!
