Mods, please don't delete my placeholder posts as this is going to be a long post and I thought it better to break it up into sections instead of having to fight with the 10000 character limit
Time for another thread about that bane of us digital photographers: keeping your data safe.
As with my
web design thread, feel free to comment and post your suggestions!
Contents:
1.
Your disk and how it can fail
2.
Steps to prevent drive failure
3.
Steps to prevent data loss
4.
Miscellaneous tips
Your Hard Drive
Unless you have money coming out of your ears and can afford a set of SSD drives, you'll have a straightforward steel box with some spinning platters inside. The read/write heads are mounted on robotic arms that whizz across the surface of the platters as the drive spins at a typical 5400-10000 RPM.
These connect to your machine through IDE or SATA or iSCSI or SAS or possibly even through the magic of unicorns.
Types of failure
I'm going to rate each instance with a number to signify how easy it is to recover yourself. A lower number means it's likely a professional job whereas a higher one means you could do it in a couple of hours.
A hard drive is a mechanical device so it's bound to fail due to wear and tear eventually. That said, I have drives that I've been using since 1999 and they still show no signs of stopping. Manufacturers will include a Mean Time Before Failure rating in the specs of the drive. This will tell you how many hours of operation it's expected to be able to do before dying a noble and honourable death.
Drives will either fail after a good while of use, or very soon after purchase. If it's the latter, then it's a manufacturing defect and you can safely RMA the drive and get a replacement.
Recoverability rating: 3
A hard drive can also fail electronically - i.e. the controller can malfunction, causing the drive to stop reading/writing correctly. This isn't the end of the world as if you have another
identical drive, you can power both on and then swap the controller boards across. The new board will take over running the disk and you should at least be able to recover your data.
Recoverability rating: 6
The motors inside the drive can burn out. This can take the form of either the arm actuators or the motor that spins the platters biting the dust. In either case, the data is recoverable, but not without spe******t kit, as you need to have the platters spinning up again and the arms moving to do anything.
Recoverability rating: 3
Another common cause of hard disk death are bad sectors. This happens when the drive is unable to read a specific location on its surface. Sometimes this is caused by the OS drivers messing up and sometimes it's a physical glitch on the surface of the disk. In either case, a bad sector isn't necessarily a huge problem and for the most part, the drive will carry on working around it. But there will come a time when the drive needs to read that sector and cannot. This will likely cause it to crash.
To prevent this, keep an eye on your SMART monitoring status. 99% of drives made this century have SMART monitoring which keeps track of a myriad different variables, one of which is possible dodgy sectors. The drive's controller picks them up and keeps track of them for you. You can download Active@ Disk Monitoring to do just that
here
If it flashes up warnings about any of the health checks, now is the time to run like wildfire down to your local electronics store, buy a USB drive and backup.
To recover a bad sector, you often need to do a low-level format of the drive. This will physically reset all sectors of the disk to 0 instead of clearing the "used" flag on them, as regular formatting does. You will lose everything and there is no chance of post-format recovery then. On the upside, your drive will live.
Recoverability rating: 7
Finally, the worst type of failure is a head crash. These are nigh-on impossible to recover from at home.
During a head crash, the read heads that skim the surface of the drive, mere nanometers above, make contact with the platter surface. If it's a brief contact, it'll cause a bad sector and you'll be spared the aftereffects that are this bastard's trademark. In most cases, however, it will score a groove along the platter, ruining the data on there and making the platter unreadable. Occasionally, the vibration in the arm will make the head bounce across the surface like a skimming stone. Either variation is a bad thing.
On the nanometer scale that disk sectors are packed together, that is the equivalent of a crack the size of the Grand Canyon suddenly appearing where a smooth surface filled with data should be.
When this happens, your system will likely freeze and become totally unresponsive. You might also hear a repetitive clicking from the drive. That's the sound of the heads flicking back and forth across the platters as it tries to work out where a whole chunk of its data is gone.
Shut down and get thee to a data recovery monkey
Recoverability rating: 1