Hard Disk Cluster: What It Is and How to Resize It

One of the most important components of our PC is the hard drive . Here we store both the operating system, the applications we use daily and personal data. Therefore a good use and maintenance of it is but extremely important. In these lines we are going to talk about what the hard disk cluster is and how you can modify it.

We find disk drives of various types and sizes that we can choose from, everything will depend on the needs of each one or the power of your equipment. We find SSD or HDD drives, USB sticks , SD cards, etc. Basically all this will help us to store our personal data in the safest way among many other things. But at the same time we must have knowledge of some basic data about its operation in order to get the most out of these storage units.

Hard Disk Cluster: What It Is and How to Resize It

What is Hard Drive Cluster

To begin with, we will tell you that when we refer to the size of the hard disk cluster, we are referring to the size of the allocation unit. Well, in order for us to understand what this is, we are talking about the minimum capacity in which a file can be saved on that hard drive. You have to know that the corresponding file systems organize the disk unit according to the size of the cluster that we assign.

This means that when a file is of a size that does not correspond to an even multiple of the cluster size, then additional disk space must be used. Thus, each cluster has a certain size that we can specify if we wish. At the same time, the file you save to disk may be larger or smaller. But if it is larger, then an additional size should be used up to the next multiple of the allocated cluster size.

Advantages and disadvantages of modifying the cluster

One thing we must be clear about is that if we do not adjust the size of the cluster or the allocation unit well , we could lose some space. As a general rule, the operating system itself takes care of all this when we format a new unit. But it is also interesting to know that we have the possibility to adjust this cluster size ourselves manually. It is precisely all this that we will talk about in the following lines.

By default the maximum cluster size for NTFS partitions is 4KB. The cluster is the smallest unit for storing and managing files on disk. Thus, a cluster can only contain one file, even if it is a single byte. If we need to save small files, we will have to configure a small clustered volume. What we achieve with all this is to improve the rate of use of space on the disk drive . On the contrary, if we need to save larger files, the volume must be configured with a larger cluster. This will help us to optimize the speed of reading and writing the data.

How to change the allocation unit size

It is worth mentioning that Windows 10 file systems organize the hard drive based on the size of the cluster we are talking about. Also known as the size of the allocation unit, this is a parameter that we have the possibility to modify. In the event that we did not specify the cluster size when formatting a partition or drive, the system selects the default values.

These are based on the size of the partition itself, so this is one of the reasons why we sometimes need to resize the cluster ourselves. This is precisely what we are going to show you next.

Modify the size from File Explorer

At this point we will tell you that the 512-byte cluster is the old standard, while the 4kb cluster is the most common today. On the other hand, the 64kb cluster size is for storing large files such as games, 3D movies, HD photos, etc. As we mentioned before, we have the possibility to change the size of the cluster according to the size of the files for better performance.

We can change this size of the hard drive in Windows 10 in two quick and easy ways. First of all we can do it from the well-known Windows File Explorer. We can access this element directly through the Win + E key combination. Thus, once we have the aforementioned File Explorer on the screen, we do the following.

First, we right-click on the partition or drive where we want to change the size of the cluster. In the contextual menu that appears we select the Format option.

formatear unidad

In the new window that will appear on the screen, we click on the Allocation unit size section, which corresponds to the size of the cluster. In the list that appears, we will be able to select the size of the cluster that we want in this specific case. From there we will be able to format the selected unit so that the changes take effect. To do this, just click on the Start button, leaving Quick Format marked.

cambiar tamaño clúster

After the disk drive formatting is complete, the cluster size will have been changed to the new value.

Resize from CMD

As we mentioned before, when it comes to changing this value we are talking about, we have two possibilities. The first, as we have seen, is carried out from Windows Explorer, while now we are going to use CMD or a command prompt window. Specifically, we are going to make use of the command called DiskPart in Windows 10. For all this that we are commenting on, we write CMD in the search box of the operating system and thus open a window at the command prompt. Of course, we recommend running this with administrator permissions by right-clicking on the entry that appears.

abrir CMD

From there, in the command prompt window that we see, we type the following command to launch the DiskPart utility.


Once this is done, we type the following commands one after the other and press Enter after each line:

list disk select disk VALOR[code]

Here we replace the word value with the number that appears in the list of the disk unit from which we want to change the size of the cluster.

[code] list partition select partition VALOR

Again here we change the value to the number in the listing for the partition we want to change the size of the cluster for.

format fs=ntfs unit=<TAMAÑO>

To finish, we just have to change the word size to the actual size of the cluster that we want to use here.