Comparing the Differences Between EBS, EFS, and S3 | A Clear Explanation of How to Choose AWS Storage

EBS, EFS, and S3 are all storage services used on AWS. However, it's a mistake to think of them all as the same "storage location." EBS is a disk used by connecting to EC2, EFS is a file area that can be shared by multiple servers, and S3 is object storage for accumulating and distributing data. Each has a different intended use.

Choosing between them without understanding the differences can lead to complex configurations and make management difficult. This article clearly explains the differences between EBS, EFS, and S3, and when and how to choose the right one for your needs.

What are EBS, EFS, and S3?

EBS, EFS, and S3 are all representative storage services used on AWS. However, treating them all as the same "storage location" will lead to choosing the wrong one. This is because EBS is storage used by connecting to EC2, EFS is storage shared by multiple servers, and S3 is storage for saving objects, and each has a different intended use.

EBS is block storage used by connecting to EC2 instances.

Amazon EBS is block storage that attaches to Amazon EC2 instances. Because it can be treated like a disk from EC2, it is used as a boot disk for operating systems and as a storage location for databases.

It can be managed as persistent storage independent of EC2 instances and supports backups using snapshots.

EFS is a file storage system that can be shared across multiple servers.

Amazon EFS is a fully managed file storage solution that uses NFSv4.1/4.0. Because it allows multiple EC2 instances to mount the same file system, it's suitable for configurations where you want to handle common files across multiple servers.

This is used when you want to access the same uploaded file across a group of web servers, or when you want to have a common workspace.

S3 is an object storage system for storing and distributing data.

Amazon S3 is object storage that stores data as objects in buckets. It is widely used for storing and distributing large amounts of data, such as images, videos, logs, backups, and static content.

Unlike disks that connect to EC2 like EBS, or shared file systems like EFS, the basic approach is to store objects individually and retrieve them as needed.

Comparison Table: Differences between EBS, EFS, and S3

One important point to remember from the comparison table is that EBS, EFS, and S3 are not the same type of storage. EBS is a disk used by connecting to EC2, EFS is a file area shared by multiple servers, and S3 is a storage location for objects; the units of storage themselves are different. When deciding which to use, you need to start by considering these differences.

What are the differences between EBS, EFS, and S3?

The differences between EBS, EFS, and S3 cannot be grasped simply by listing their uses. What you need to look at is the difference in whether data is treated as disk, shared as files, or stored as objects.

The way the data is stored is different.

The first difference lies in how data is stored. EBS is block storage and is treated as a disk from EC2. EFS is file storage and allows you to share directory and file hierarchies directly. S3 is object storage and is used by retrieving objects stored in a bucket as needed.

Even though they share the same storage location, the underlying assumptions are quite different. EBS is for server disks, EFS is for shared file areas, and S3 is for storing objects.

The connection method and usage scenario are different.

The connection methods also differ. EBS is storage that is attached to EC2 instances and can be treated like a disk from the instance. EFS is shared file storage that is mounted via NFS. S3 is a service that stores and retrieves objects via APIs, consoles, CLIs, etc., and is not intended to be used by connecting to a server.

This difference manifests as a difference in how they are used. EBS is a disk attached to a server, EFS is a file area shared by multiple servers, and S3 is a storage location accessed by applications and services.

Whether or not it can be shared across multiple instances differs.

When you want to handle the same data across multiple instances, the service you should choose will also change.

EFS can be used as a shared file system because it allows multiple EC2 instances to mount the same file system.

EBS volumes are generally used as persistent disks for a single instance. As an exception, io1/io2 volumes can sometimes be attached simultaneously to multiple compatible instances within the same Availability Zone using Multi-Attach.

S3 can be accessed from multiple servers and services, but it is not a shared file system.

This difference directly impacts the configuration. The key distinction is: EFS for handling the same files across multiple servers, EBS for data contained within a single EC2 instance, and S3 for a common storage location accessed by multiple systems.

The concept of scalability is different.

There are also differences in how they approach expansion. EFS is a file storage system that expands and contracts according to changes in file volume. S3 is also suitable for storing large amounts of data and can be used without having to worry too much about storage capacity. In contrast, EBS is a storage system that is used while designing the size and performance of the volume.

In short, EFS and S3 are better suited to handling fluctuating data volumes, while EBS relies heavily on designing and using disks that meet specific requirements. EBS is suitable for situations where you want to closely monitor capacity and performance, while EFS and S3 are better for storing shared files or large amounts of data that fluctuate in size.

How should EBS, EFS, and S3 be used differently?

EBS, EFS, and S3 are not chosen based on superiority or inferiority. The deciding factor is whether you want to use them by connecting to EC2, sharing across multiple servers, or using them as a data storage location. Different roles require different services.

If you're going to use it as a disk for the OS or database, then EBS is the way to go.

EBS is well-suited for OS boot disks and database storage locations. EBS is block storage that attaches to EC2 instances and can be treated as a disk from the instance's perspective. For applications that are self-contained within a single EC2 instance, or configurations with data that requires continuous reading and writing, it's natural to start by considering EBS as the core storage solution.

Conversely, it's not suitable if you want to share the same file across multiple servers. EBS should be considered as a disk to use when connected to EC2.

If you want to handle the same file across multiple instances, use EFS.

If you need to access the same files from multiple EC2 instances, EFS is a good option. EFS can be used as shared file storage, allowing multiple instances to mount the same file system simultaneously. It's suitable for situations where you want to access a common uploaded file across a group of web servers, or when you want multiple servers to use the same workspace.

Using the same file system is a simpler design than having each server have its own separate disk and needing to synchronize them. Even with a multi-server configuration, you don't need to create a separate file sharing mechanism.

For saving images, videos, logs, and backups, use S3.

S3 is a strong contender for storing large amounts of data, such as images, videos, logs, and backups. S3 is object storage, designed for storing data in buckets and retrieving it as needed. This is why it is widely used for log storage, static content delivery, and backup storage.

S3 is not meant to be used as a replacement for EC2 disks. It should be thought of as a storage location for accumulating, storing, and distributing data as needed, rather than as storage directly attached to the server.

If you're unsure, consider whether you want to "connect and use it," "share it," or "use it as a storage location."

When in doubt, it's quicker to think in terms of "how you want to use it" rather than "what you want to save." If you want to connect to EC2 and use it as a disk, use EBS; if you want to share the same file across multiple servers, use EFS; and if you want to use it as a data storage location or distribution source, use S3.

While all three are storage locations, their roles are not the same. EBS is a disk attached to a server, EFS is a shared file area, and S3 is a storage location for objects. If you categorize them by how you will use them, rather than what you will use them for, it will be easier to narrow down which service you should choose.

Common questions when comparing EBS, EFS, and S3

EBS, EFS, and S3 have different roles and cannot be simply substituted for each other. Common sources of confusion include situations where you might think, "Can't I just use S3 instead?" or "Is it okay to use either EBS or EFS?"

Will S3 replace EBS or EFS?

A standard S3 bucket is neither a disk that attaches to an EC2 instance like EBS, nor is it used directly as shared file storage like EFS. However, as of 2026, Amazon S3 Files adds a configuration that allows data on S3 to be mounted and handled as a shared file system.

Therefore, you cannot simply replace EBS, which is used as the storage location for OS disks and databases, with S3. The same applies to file areas shared with EFS. S3 should be considered as a storage location for images, videos, logs, backups, and static content.

Which should I choose, EBS or EFS?

What you should be looking at is not whether the performance is superior or inferior, but whether you need a disk for a single server or a file area that needs to be shared among multiple servers.

EBS is the first choice for storing OS disks, local data, and databases. If you want to access the same files across multiple EC2 instances, choose EFS. If you're unsure, you can decide by using EBS for "disks attached to the server" and EFS for "shared file areas."

Are there any cases where they are used together?

Yes, it's possible. In fact, since they serve different purposes, it's more natural to use them together. For example, one configuration involves placing the EC2 OS and application execution area on EBS, and files that need to be shared across multiple instances on EFS. It's also common to combine this with S3 for backups, logs, and static content storage.

Rather than unifying everything into one of the three, separating them by function ensures consistency in where each item should be placed.

Summary

EBS, EFS, and S3 are all AWS storage services, but they serve different purposes. The basic distinction is: EBS is for disks connected to EC2 instances; EFS is for file areas shared across multiple servers; and S3 is for storing images, videos, logs, and backups.

When choosing, the decision should be based on how you want to use it, not what you're storing. EBS is for connecting to a server, EFS for sharing, and S3 for storage.