Do I need to say that in everyday work any user has to deal with formatting hard drives or removable drives in the form of the most common flash drives or memory cards? When this process is activated, most of us usually do not pay attention to the size of the allocation unit called the cluster, leaving this parameter to the discretion of the operating system itself. In principle, this approach is correct. However, sometimes it is useful to change this value. What is it for and what factors should be taken into account when choosing, then we'll talk.
What is the cluster size?
If anyone does not know, on absolutely all drives the files recorded on them are stored not in the form of solid objects, but in the form of parts distributed over clusters, which arepeculiar cells into which a hard drive or the same flash drive is broken. In Windows systems, there is a strict rule associated with the fact that the OS, when using (and formatting) the media, independently reserves the minimum amount of disk space for storing information. This is the size of the allocation unit.
Depending on the modification of the file structure and volume size, the minimum size can be either 512 bytes or 4 KB. The OS itself sets the required size based on the automatic recognition of such options. But it is not always advisable to use them.
How to choose the size of the allocation unit when formatting: the main criteria affecting the setting of preferred options
First of all, you need to clearly understand that the choice of the user is significantly influenced by a number of factors that the operating system itself may not take into account. Among the most important are the following:
- preferred FS;
- sizes of saved files;
- write / read speed when working with media.
As a result, we can single out the frequency of OS access to the storage medium when some actions related to copying or moving information are performed with the files present on it.
File structures used for different types of drives have their own limitations, and their application to certain types of devices is strictly regulated.
The most advanced today is NTFS, however, when installing some versions of Windows from removable drives (flash drives), it cannot be used.
If we are talking about, say, choosing the size of the distribution unit when formatting a hard disk in FAT32 or NTFS, it is better to give preference to the second type, since FAT32 does not support modern HDDs and SSDs with a capacity of more than 2 TB, and does not allows you to record files larger than 4 GB. And the automatic settings offered by Windows itself do not need to be changed in most cases. The same theoretically applies to flash drives.
However, sometimes it is advisable to use the ext/exFAT FS for memory cards.
Now let's decide on one of the most important parameters that determine the choice of allocation unit size when formatting a flash drive, in relation to NTFS file structures, in which the minimum cluster size is 4 KB or 4096 bytes.
Immediately, you should focus on the fact that this is exactly the minimum size, below which it will not work to set or use the value. Now consider the simplest example. Let's say you're copying or saving a file on a flash drive that is theoretically 1 KB in size. It is recorded in one cluster and occupies it entirely. That is, in fact, 3 KB can be attributed to unaccounted for losses. And nowimagine how much free space would be wasted if there were a lot of small objects!
One more example. You set the allocation unit size to 32 KB and place text documents on the drive that are much smaller than the specified minimum size (for example, 4 KB each). Anyway, each of them will take the same 32 KB, and 28 KB for each object will simply be lost.
Reliability of the drive in operation, speed of reading and frequent access to the drive
Now let's come to understanding the correctness of choosing the minimum size of the allocation unit from a slightly different angle. Suppose you have set the cluster size too small, but have written a very large file (for example, audio or video formats) to the drive. When copying or even playing music or a movie, the system will access the device where the original file is located more often. In turn, such too frequent access to the device can provoke its early failure. But when you set a larger value for the cluster size, the frequency of access will be significantly reduced, which will increase the life of the storage medium.
Also, playing or copying audio and video from a drive with a 4K cluster size will be slower than setting the same value at 64K.
Grand summary and recommendations
Thus, summing up all of the above, we can decide onpreferred allocation unit size when formatting any of the known storage media:
- for hard drives, it is better not to change the automatically installed parameters in Windows;
- when writing small files to flash drives, it is recommended to reduce the size to the minimum threshold compatible with the size of the files themselves;
- when writing or saving heavy files, it is better to increase the minimum size to a known limit.
In general, if we are talking about removable devices, first decide what kind of information will be recorded on them, and only then set the necessary options.