You’ve probably heard this before. There are two types of hard drive – those that have failed and those that will fail. It’s this maxim that makes backups so essential.
The trouble is, many of us don’t learn the lesson about backups until it’s too late.
Almost every computer user has suffered some kind of data loss or disk failure and are left scrambling to recover precious business files, photos or other irreplaceable media.
For those times, we need data recovery tools that can get our data back before it disappears into the ether.
Types of data loss
Before we start looking at Prosoft Engineering’s data recovery tools, it’s important to understand what we’re talking about when it comes to data loss and recovery.
Hardware failure: Old-style hard drives store data on an array of platters that spin and are read by a head. It’s a bit like a record or CD player. As they’re a mechanical system, components can fail. The head or its mechanism, or the platters, can be damaged. Or the motor that spins the disks can break down.
Data recovery from a hardware failure can be difficult. It may be possible to read data from a dying drive for a limited time. However, if the drive is completely dead experts can disassemble to drive and rebuild it. This is time consuming and potentially expensive.
It’s important to note that although solid-state drives or SSDs, lack moving parts, they can fail. Electronic components can be affected by power supply issues and most SSDs can only be written of a finite number of times. So, an older SSD can ‘wear out’ if it’s heavily used.
Software failure: When an application writes data to your hard drive, it relies on the operating system. If that process is interrupted, such as if there’s a power failure while saving a file, it’s possible that the computer’s filesystem becomes corrupted.
If that happens, your system may start behaving erratically or, in extreme cases, you may lose complete access to your system.
How can you tell what’s going on?
Macworld Australia decided to put the Prosoft Engineering Data Rescue toolkit in the hands of an expert.
Derek Rawson has been fixing Macs and helping Mac users for many years. He’s helped me out, replacing a dead hard drive in an iMac and upgrading my supposedly un-upgradeable Mac mini with an SSD and he has a great reputation for fixing problems.
Data recovery is a very tricky business. Being able to diagnose the difference between a hardware problem and a software problem is not always straightforward. And with hardware problems, there’s a balancing act between acting quickly, to recover whatever you can before the drive totally fails, and carrying out a more exhaustive process that might recover all the at-risk data.
“When you’re working with failed hard drives, it can be a scary thing,” says Rawson. “You’re thinking you need to get the data off quickly so the drive doesn’t pack up on you. You can’t mess around with what you do.”
In Rawson’s view, there’s a very fine line between a dead drive and one with recoverable data.
- Data Rescue ONE – this is a 500GB hard drive that’s loaded with a bootable partition with data recovery tools and space for storing recovered files.
- Data Rescue 4 – a bootable USB stick that contains Prosoft Engineering’s data recovery tools. It’s similar to Data Rescue ONE, without the disk space for file recovery.
- Drive Genius 4 – a bootable USB stick with Prosoft Engineering’s Mac defrag software which, they say, will boost your Mac’s performance. We’re not looking at this as our focus is on data recovery.
Rawson’s experiences using the Data Rescue tools were somewhat mixed.
In the hands of an expert
Rawson’s first concern stemmed from Data Rescue ONE’s limited capacity. Once the Data Rescue ONE drive was connected to a dying Mac, he could examine the drive and then, potentially, recover files.
Data Rescue ONE comes in four versions – three are pitched at home users with the fourth directed at professionals. Although Rawson tested the 500GB drive (US$149) and 16GB USB disk (US$59), it also comes in a 1TB version. That disk capacity sets a hard limit on how much data the device can actually save.
The 1TB option costs US$179 but an unlimited version, that is pitched at professionals like Rawson, is available as an annual subscription of US$419. There are software-only options as well. The standard version of Data Rescue (US$99) supports an unlimited number of files but just five drives. And there’s a US$299 annual subscription Pro option that comes on a USB 3.0 bootable drive and is completely unlimited.
As an experienced practitioner, Rawson has used a number of different tools over the years for dealing with file system issues and carrying out block-level data cloning.
It’s important to note that block-level cloning is different to what tools like Carbon Copy Cloner and Super Duper do. Those are great for creating bootable backups. But, for data recovery, they are aren’t effective as they rely on the drive being mountable. A block-level clone doesn’t need to the disk to mount a filesystem – it just needs the disk to be physically connected to the computer.
One of the success stories Rawson had was in recovering data from a failed 1TB hard drive. Fortunately, the drive wasn’t full, so the Data Rescue ONE drive with 500GB of capacity was adequate for saving about 240GB of data that was on the drive.
The first step in the process was carrying out a block-level clone of the hard drive. Given the precarious state of the failing disk, this took over a week.
Rawson then used Data Rescue ONE to successfully recover almost 80% of the data that would have been otherwise lost.
Rawson, as an experienced operator, relies on the Terminal for some of the actions he takes when recovering data and dealing with drives that won’t play nicely. He found that when booting from Data Rescue ONE, he was unable to access the Terminal.
He also noted the complexity of the data recovery process requires a number of decisions to be made.
For example, would it better to carry out a block-level clone and then attempt data recovery from that or should you recover directly from the disk? In some cases, a fast scan might not reveal any recoverable data but a deep scan will. However, a deep scan is a time consuming process and may not be advisable on a dying drive.
Rawson suggests that some extra guidance for users – particularly the home users many of the Data Rescue products are pitched at – would be useful.