20 Amazon Elastic File System (Amazon EFS) Interview Questions and Answers

Amazon Elastic File System (Amazon EFS) is a cloud-based file storage system that provides a secure and cost-effective way to store and share data across multiple Amazon Web Services (AWS) accounts. As a job applicant, having a strong understanding of Amazon EFS can be a valuable asset. In this article, we review some commonly asked Amazon EFS interview questions and provide tips on how to answer them.

Amazon Elastic File System (Amazon EFS) Interview Questions and Answers

Here are 20 commonly asked Amazon Elastic File System (Amazon EFS) interview questions and answers to prepare you for your interview:

1. Can you give me a brief overview of Amazon EFS?

Amazon Elastic File System (EFS) is a fully managed, cloud-based file storage service that provides simple and cost-effective storage for use with Amazon EC2 instances. It allows users to create and configure file systems quickly and easily, without the need for complex hardware or software setup. With EFS, customers can store and access files from multiple EC2 instances simultaneously, making it ideal for applications requiring shared data across multiple servers. Additionally, EFS supports both NFSv4 and SMB protocols, allowing customers to mount their file system on Linux, Windows, and macOS clients. Finally, EFS offers high availability and durability, ensuring that customer data remains safe and accessible even in the event of an outage.

2. What are the main use cases for using Amazon EFS?

Amazon EFS is a cloud-based file storage system that provides users with the ability to store and access files from multiple Amazon EC2 instances. It is designed for use cases such as web serving, content management systems, media streaming, application development, analytics, and data processing.

One of the primary use cases for Amazon EFS is web hosting. With Amazon EFS, customers can easily host their websites on multiple EC2 instances without having to manage separate file systems for each instance. This allows them to quickly scale up or down depending on their needs. Additionally, Amazon EFS supports high availability, meaning that if one instance fails, the website will still be available from another instance.

Another common use case for Amazon EFS is content management systems (CMS). By using Amazon EFS, customers can store all of their CMS files in one central location, allowing them to quickly and easily update their content across multiple EC2 instances. This makes it easier to keep their content consistent and up-to-date.

Finally, Amazon EFS is also used for media streaming applications. Customers can store their media files in Amazon EFS and then stream them to multiple EC2 instances. This allows them to quickly scale up or down depending on their needs, while ensuring that their media files are always available.

3. Does Amazon EFS support encryption at rest and in transit? If yes, then how can it be configured?

Yes, Amazon EFS does support encryption at rest and in transit. Encryption at rest is enabled by default when creating a new file system, using the AWS Key Management Service (KMS) to manage the encryption keys. This ensures that data stored on disk is encrypted with 256-bit Advanced Encryption Standard (AES-256).

In addition, Amazon EFS also supports encryption in transit via Transport Layer Security (TLS). TLS can be configured for both NFSv4 and mount targets, allowing clients to securely connect to an Amazon EFS file system over the internet or through a VPC endpoint. To configure TLS, users must create an SSL certificate and associate it with their Amazon EFS file system.

4. Is there any way to encrypt data stored on an EFS file system without having to re-encrypt all existing files?

Yes, Amazon EFS provides a feature called Server-Side Encryption (SSE) that allows users to encrypt data stored on an EFS file system without having to re-encrypt all existing files. SSE uses the AWS Key Management Service (KMS) to manage encryption keys and automatically encrypts all new files written to the EFS file system. Additionally, SSE can be used in conjunction with other security measures such as Access Control Lists (ACLs) or Security Groups to further protect sensitive data.

5. How do we access data stored on an EFS file system from an EC2 instance?

Accessing data stored on an Amazon EFS file system from an EC2 instance is a straightforward process. First, the user must create an EFS file system and mount it to their EC2 instance. This can be done through the AWS Management Console or using the AWS Command Line Interface (CLI). Once the file system has been mounted, the user will have access to all of the files stored in the EFS file system. The user can then read, write, and modify any of the files as needed. Additionally, the user can also set up permissions for other users to access the file system if desired.

6. What is the best way to share data securely between multiple AWS accounts?

The best way to securely share data between multiple AWS accounts is through Amazon Elastic File System (Amazon EFS). Amazon EFS provides a simple, scalable, and secure file storage solution that can be used across multiple AWS accounts. It allows users to create shared file systems that are accessible from any of the connected AWS accounts. This makes it easy for teams to collaborate on projects without having to worry about security or access control issues. Additionally, Amazon EFS supports encryption at rest and in transit, making sure that all data stored and transferred is kept safe and secure. With its scalability and ease of use, Amazon EFS is an ideal solution for securely sharing data between multiple AWS accounts.

7. What’s the difference between lifecycle management policies and automatic backups?

Lifecycle management policies and automatic backups are two different features of Amazon EFS. Lifecycle management policies allow users to define rules for when files should be moved from the active storage tier to the infrequent access tier, or even archived in Amazon S3 Glacier. This helps reduce costs by allowing users to store data that is not frequently accessed at a lower cost.

Automatic backups, on the other hand, provide an additional layer of protection against accidental file deletion or corruption. With this feature enabled, Amazon EFS will automatically create point-in-time snapshots of the file system every 12 hours. These snapshots can then be used to restore the file system to its previous state if needed.

8. What happens if I delete a file system that contains active mount targets?

If a file system containing active mount targets is deleted, the mount targets will be automatically deregistered and all associated resources such as security groups and network interfaces will also be removed. The data stored in the file system will remain intact until it is manually purged by an Amazon EFS administrator. If the file system is not purged within 30 days of deletion, then the data will be permanently lost. It is important to note that any applications or services relying on the deleted file system will no longer function properly until they are reconfigured with a new mount target.

9. What do you understand about performance mode? Which one should be used in certain situations?

Performance mode is a feature of Amazon EFS that allows users to customize the performance of their file system. Performance mode can be set to either General Purpose or Max I/O, and each setting provides different levels of throughput and latency.

General Purpose mode is best suited for applications with moderate I/O requirements such as web servers, content management systems, and development environments. This mode offers a balance between cost and performance, providing consistent low-latency access to files stored on the file system.

Max I/O mode is designed for applications that require high levels of throughput and low latency. Examples include big data analytics, media processing, and scientific computing workloads. With this mode, customers can achieve up to 10x higher throughput than with General Purpose mode. However, it comes at an increased cost.

In summary, when choosing which performance mode to use, customers should consider the type of application they are running and its specific I/O requirements. For applications with moderate I/O needs, General Purpose mode is recommended. For applications requiring high throughput and low latency, Max I/O mode is the better choice.

10. What is the maximum size of a single file that can be uploaded to an EFS file system?

The maximum size of a single file that can be uploaded to an Amazon EFS file system is 5 TiB. This limit applies to both individual files and the total amount of data stored in the file system. The maximum number of files that can be stored in an EFS file system is limited only by the storage capacity of the underlying hardware, which can range from hundreds of terabytes to petabytes. Additionally, there are no limits on the number of concurrent connections or throughput for an EFS file system.

11. What is the difference between provisioned throughput and burst throughput?

Provisioned throughput is the amount of throughput that Amazon EFS guarantees to a file system. This means that, regardless of usage patterns or other factors, Amazon EFS will provide the specified level of performance for the duration of the provisioned throughput period. Burst throughput, on the other hand, is an additional burst of throughput that can be used when needed. It allows customers to exceed their provisioned throughput levels for short periods of time, allowing them to handle sudden spikes in demand without having to increase their provisioned throughput.

12. Is it possible to change the default security group associated with my mount target?

Yes, it is possible to change the default security group associated with a mount target in Amazon EFS. This can be done by navigating to the Amazon EC2 console and selecting the “Security Groups” option from the left-hand menu. From there, you will need to select the appropriate security group for your mount target and click on the “Edit Inbound Rules” button. You can then add or remove rules as needed to customize the security settings for your mount target. Once you have finished making changes, make sure to save them before exiting the page.

13. What happens when two or more clients try to write to the same file simultaneously?

When two or more clients attempt to write to the same file simultaneously on Amazon EFS, a conflict can occur. To prevent this from happening, Amazon EFS implements an optimistic concurrency control system that allows multiple clients to read and write to the same file without any conflicts. This is done by allowing each client to make changes to the file in their own private copy of the file. When the client attempts to save the file, Amazon EFS will check if there have been any other changes made to the file since the last time it was saved. If there are no conflicting changes, then the file will be updated with the new changes. However, if there are conflicting changes, then the client will receive an error message indicating that the file could not be saved due to a conflict.

14. What’s the best way to check whether an NFS client has reached its connection limit?

The best way to check whether an NFS client has reached its connection limit is to use the Amazon Elastic File System (Amazon EFS) console. The console provides a graphical interface that allows users to view their current connections and determine if they have exceeded the maximum number of connections allowed. Additionally, users can also use the AWS Command Line Interface (CLI) to query the status of their NFS clients. With the CLI, users can run commands such as “aws efs describe-mount-targets” which will provide information about the mount targets associated with the file system, including the number of active connections. This data can then be used to determine if the client has reached its connection limit.

15. How does Amazon EFS compare with other network file systems such as CIFS/NFS?

Amazon EFS is a cloud-based file system that provides users with the ability to store and access data from multiple Amazon EC2 instances. Compared to other network file systems such as CIFS/NFS, Amazon EFS offers several advantages. Firstly, Amazon EFS allows for scalability of storage capacity without any disruption in service. This means that users can easily increase or decrease their storage needs on demand, allowing them to save money by only paying for what they need. Secondly, Amazon EFS also offers high availability and durability, meaning that files stored on the system are always available and protected against hardware failure. Finally, Amazon EFS supports both NFSv4 and SMB protocols, making it compatible with most existing applications and operating systems.

16. Are there any limitations to using Amazon EFS with Windows operating systems?

Yes, there are some limitations to using Amazon EFS with Windows operating systems. First, the maximum file size that can be stored on an Amazon EFS volume is limited to 47.9TB. Additionally, only certain versions of Windows Server are supported by Amazon EFS, including Windows Server 2008 R2 and later. Furthermore, Windows clients must use SMB 3.0 or higher in order to access files stored on Amazon EFS volumes. Finally, Amazon EFS does not support Windows NTFS permissions, so users will need to manage their own security policies for any data stored on Amazon EFS.

17. What types of storage volumes are supported by Amazon EFS?

Amazon EFS supports two types of storage volumes: Standard and Infrequent Access (IA). Standard storage is designed for frequently accessed data, while IA storage is optimized for infrequently accessed data. Both types of storage offer the same performance characteristics, but IA storage offers a lower cost per gigabyte stored. Amazon EFS also provides an optional Lifecycle Management feature that can be used to automatically move data between Standard and IA storage tiers based on usage patterns. This helps customers optimize their costs by ensuring that they are only paying for the type of storage they need.

18. Is it possible to resize an EFS volume after creation? If yes, then how?

Yes, it is possible to resize an Amazon EFS volume after creation. This can be done by using the AWS Management Console or the AWS Command Line Interface (CLI). To resize a volume with the console, users must select the file system they wish to modify and then click on “Modify File System”. From there, they will be able to adjust the size of their volume as needed.

To resize a volume with the CLI, users must first use the describe-file-systems command to get the ID of the desired file system. Then, they can use the modify-file-system command to set the new size for the volume. Once the modification is complete, users should run the describe-file-systems command again to confirm that the changes have been applied.

19. What are some common mistakes made when working with Amazon EFS?

One of the most common mistakes made when working with Amazon EFS is not properly configuring security groups. Security groups are used to control access to resources, and if they are not configured correctly, it can lead to unauthorized access or data leakage. Additionally, users should be aware that Amazon EFS does not support encryption at rest, so any sensitive data stored on the system must be encrypted before being uploaded.

Another mistake often seen with Amazon EFS is failing to monitor performance metrics. It’s important to keep an eye on latency, throughput, and other performance indicators in order to ensure optimal performance. If these metrics are not monitored regularly, it could result in poor user experience or even outages.

Finally, some users may forget to back up their data. While Amazon EFS provides a highly available storage solution, it is still important to have backups in place in case of unexpected events such as hardware failure or accidental deletion. Without proper backups, data loss could occur.

20. In your opinion, what are the most important features of Amazon EFS?

In the opinion of this individual, Amazon EFS offers a number of important features that make it an attractive choice for cloud storage. Firstly, Amazon EFS provides scalability and flexibility, allowing users to easily increase or decrease their storage capacity as needed. This makes it ideal for applications with unpredictable workloads or those that require large amounts of data. Secondly, Amazon EFS is highly available, meaning that files stored on the system are always accessible and can be accessed from multiple locations. Thirdly, Amazon EFS also offers high performance, enabling fast access times and low latency when accessing files. Finally, Amazon EFS is secure, providing encryption at rest and in transit, making it suitable for storing sensitive data.