Instance Storage

Question 1

EBS Volume

Does data get lost when EC2 instances associated to it get terminated ?
Can a single EBS unit be mounted on multiple EC2 instances?
Are they bound to specific Availability Zone?
Explain the concepts and usecase of snapshots.

Network USB stick, what is the default size

Answer 1

• It is a network drive you can attach to your instances while they run.
• It allows instances to persist data, even after they get terminated.
• They can only be mounted to one instance at a time.
• EBS are network drives, hence they can be detached from EC2 isntances and attach to other instances instantly.
• An EBS can’t be connected with multiple EC2 instances simulatenously. But, can be done through mutli-attach feature of EBS (limited to 16 instances simultanously). [Recommended approach is to ues AWS EFS service.]
• EBS volumes are locked to specific AZs.
• Use snapshots we can copy and replicate EBS volume in a different AZ to get attched to an instance in a different AZ.

Multiple EBS can be attached to a single instance

30 GB of free EBS storage (either SSD or HDD)

Question 2

What is the default configuration of an root EBS volume for when an instance is terminated?
Is the default configuration of the secondary EBS volume the same as root EBS volume?

Answer 2

By default, when an instance is terminated in AWS, the root EBS (Elastic Block Store) volume is deleted automatically, removing all data stored on it.

For secondary EBS volumes, the default behavior upon instance termination depends on how they were created. If you created additional EBS volumes (not the root volume) and attached them to your instance, the default action is that these additional volumes are not deleted. However, you can choose to enable or disable the “Delete on Termination” setting for these secondary volumes during creation or modification. If “Delete on Termination” is enabled for secondary volumes, they will be deleted upon instance termination; otherwise, they remain intact.

So, by default, the root EBS volume is deleted upon instance termination, but the behavior for secondary volumes depends on the “Delete on Termination” setting at the time of their creation or modification.

Question 3

EBS Snaptshot

What is snapshoting?
What are the different snapshot features?
What are the use cases ?

Answer 3

Concept of making a backup of a EBS volume at a point in time.
Not necessary to detach volume to do snapshot, but recommended
You can copy a snapshot accross AZ or region.
- EBS snapshot Archive (Moves snapshot to archive tier), cheapest approach.
- Recycle Bin for EBS Snapshot (Setup rule for retaining deleted snapshot), data can be retained min 1 day upto 1 year.
- Fast Snapshot Restore (Forceful initialization of snapshot), most expensive

Question 4

AMI

Full form ?
What does it do ?
What is the AWS scope of AMIs?
Are AMIs readily available ?

Answer 4

• Amazon Machine Image are customized booting packages.
• Consists of software. configurations, OS, etc, necessary on an EC2 instance
• Locked down to Region but can be copied to different regions after they are made.
  1. Public AMIs; AWS provided
  2. Own AMI; User makes and maitains own AMI
  3. AWS Marketplace AMI; Someone else sells, or User can also sell their own created AMI.

Booting is the process of installing foundational software

Booting is the first most process initiated whenever a new instance is sanctioned or switched on.

Question 5

Instance Store

What makes instance stores better than EBS storage ?
Do they loose their data when EC2 instance is terminated ?
How do you deal with Risk of data loss if hardware fails

Answer 5

• EBS volume are network drives with good but limited performance in terms of IO operations.
• Instance store are high performance hardware disk that provide faster I/O operations.
• When an EC2 instance is terminated they will loose their data.
• Use case: its best used for good cache/ buffer/ scratch data/ temporary content

Risk of data loss can be dealt with replication by the user, aws isn’t responsible for data loss at EC2 instance store in the scenario the user terminates the instance

Question 6

What is Amazon EFS?

How is Amazon EFS defined in the context of AWS?

Explain the concept of Amazon EFS.

How does Amazon EFS work for storing data?

Summarize the significance of using Amazon EFS in AWS.

Answer 6

Answer: Amazon EFS (Elastic File System) is a fully managed, scalable file storage service in AWS. It provides a simple and scalable file system for use with Amazon EC2 instances and other AWS services. Amazon EFS supports the Network File System (NFS) protocol, allowing multiple instances to access and share data concurrently.

Real world Use-Case: Imagine a scenario where multiple EC2 instances need to share files for a web application. Amazon EFS allows these instances to mount the same file system, ensuring consistent and shared access to files across all instances.

Amazon EFS is designed for scenarios where scalable and shared file storage is required. It is well-suited for applications and workloads that involve multiple instances requiring concurrent access to shared data.

Amazon EFS is a valuable storage solution that enables users to create scalable and shared file systems in the AWS cloud. It provides flexibility for applications with dynamic storage needs, allowing multiple instances to access and share data seamlessly through the NFS protocol.

Question 7

What are the differences between EFS and EBS?

How do EFS and EBS differ in their functionalities?

How are EFS and EBS used differently for storing data?

Answer 7

• EFS (Elastic File System) is a scalable file storage service that allows multiple EC2 instances to share data across a network, while EBS (Elastic Block Store) is a block-level storage service primarily used for single EC2 instance storage.
• EFS supports simultaneous access from multiple instances, making it suitable for shared access, whereas EBS is attached to a single instance at a time.

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EFS is like a library where all your friends can borrow books together, while EBS is more like your personal notebook that only you can write in. EFS allows many computers to share files, like friends sharing books, whereas EBS is for one computer to keep its own stuff safe, like your own special notebook.

EFS is expensive compared to EBS

EFS is for sharing files among many computers, and EBS is for individual computers to store their own data separately.

Question 8

Which Amazon Elastic Block Store (EBS) volume types can be used as boot volumes for EC2 instances?

Answer 8

• General Purpose SSD (gp3 and gp2): Balanced performance and cost-effective. Suitable for various workloads.
• Provisioned IOPS SSD (io2 and io1): Designed for high-performance and critical applications, allowing specification of IOPS.

Good Performance GPs and Pro IOPS for Boots