May 17, 2018 at 17:44Apple Fusion Drive, saving data when replacing a hard drive
Recently, there has been a sharp increase in the number of cases of irrecoverable data loss associated with a lack of understanding of the features of Apple Fusion Drive technology.
The purpose of the note is to draw attention to these features and to warn users of Apple devices with Fusion Drive technology from actions leading to the destruction of information when replacing a hard drive.
The correct sequence of actions:
The sequence leading to data loss:
Apparently, at the moment, the life cycle of hard drives in a large number of Apple devices with Fusion Drive technology (hereinafter referred to as FD) is coming to an end. And users are massively turning to the appropriate service centers, where they replace hard drives with serviceable ones.
Then, many of them, independently or with the help of specialists, try to extract data from the old disk. And at this moment they are faced with the “reverse side” of FD, which makes the complete restoration of information already impossible.
In general, practice shows that service center employees do not always seek to delve into the features that must be taken into account to save customer data. Therefore, if you keep important information on the FD repository, it is useful to understand in general terms how it works.
FD is a combination of two drives, one of which is a solid-state SSD of small size, and the second is a regular hard drive (or, in the case of laptops, a laptop). At the same time, the user sees such a device in the system as one logical volume with a total capacity equal to the sum of the SSD and HDD capacities.
As you can already guess from the total volume, SSD is used directly for storing information, and not as a cache. In order to reduce the average access time, the operating system places the most requested part of the data on it. Thus, among other things, there is overhead information of file systems and frequently used user files.
Part of the data is placed on the SSD immediately, another part is moved there gradually, in automatic mode, as information about user activity accumulates. As a result, the contents of the least requested files appear on the slower hard drive.
When initialization, formatting and reinstallation of the operating system is performed after replacing the HDD, not only the most relevant user data, but also the file system overhead is destroyed on the SSD, which is the key to the integrity of the files left on the old HDD.
As a result, without the information contained on the SSD, in most cases it is possible to recover from the replaced hard drive only individual pieces of little significant files.
The purpose of the note is to draw attention to these features and to warn users of Apple devices with Fusion Drive technology from actions leading to the destruction of information when replacing a hard drive.
Briefly
The correct sequence of actions:
- Saving all important information. If the hard drive fails and you can’t do it yourself - contact a specialist.
- Replacing a drive in a computer or laptop and then returning to service.
The sequence leading to data loss:
- Replace the drive and return the device to use.
- An attempt was made to copy the necessary files from the hard disk removed from the device.
More details
Apparently, at the moment, the life cycle of hard drives in a large number of Apple devices with Fusion Drive technology (hereinafter referred to as FD) is coming to an end. And users are massively turning to the appropriate service centers, where they replace hard drives with serviceable ones.
Then, many of them, independently or with the help of specialists, try to extract data from the old disk. And at this moment they are faced with the “reverse side” of FD, which makes the complete restoration of information already impossible.
In general, practice shows that service center employees do not always seek to delve into the features that must be taken into account to save customer data. Therefore, if you keep important information on the FD repository, it is useful to understand in general terms how it works.
FD is a combination of two drives, one of which is a solid-state SSD of small size, and the second is a regular hard drive (or, in the case of laptops, a laptop). At the same time, the user sees such a device in the system as one logical volume with a total capacity equal to the sum of the SSD and HDD capacities.
As you can already guess from the total volume, SSD is used directly for storing information, and not as a cache. In order to reduce the average access time, the operating system places the most requested part of the data on it. Thus, among other things, there is overhead information of file systems and frequently used user files.
Part of the data is placed on the SSD immediately, another part is moved there gradually, in automatic mode, as information about user activity accumulates. As a result, the contents of the least requested files appear on the slower hard drive.
When initialization, formatting and reinstallation of the operating system is performed after replacing the HDD, not only the most relevant user data, but also the file system overhead is destroyed on the SSD, which is the key to the integrity of the files left on the old HDD.
As a result, without the information contained on the SSD, in most cases it is possible to recover from the replaced hard drive only individual pieces of little significant files.
Options for saving data
- Backup.
- If the hard drive is working, but for some reason you want to replace it, first save all the important files to another drive.
- If the hard drive fails and there is no actual backup, bring the entire device to recovery without attempting to replace the hard drive and reinstall the system.
- If you still need to urgently return the laptop or computer to use, save a sector-by-sector copy of the SSD before replacing the hard drive.