EC2 Instance Storage Flashcards by Heather OBrien

Describe EBS (Elastic Block Store) volumes?

EBS is a network drive you attach to your instances while they run. Allows you to persist data in instances, even after they’re terminated. Think of them as a network drive. Uses the network to communicate, so some latency.

Can only be be mounted to one instance at a time, except for multi-attach instances.

EBS is bound to one AZ. To move EBS data across to another AZ, you must use a snapshot.

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What is the “Delete on Termination” attribute on EBS?

Controls the EBS behavior when an EC2 instance is terminated. Can be used to preserve root volume when instance is terminated.

By default, root BES volume is deleted, another others aren’t deleted.

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Describe EBS snapshot

Snapshots make a backup (snapshot) of your EBS volume at a point in time.

You can copy snapshots across AZ or Region.

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True or False

You must first detach an EBS volume to create a snapshot.

False.

But it is recommended.

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What are Amazon Machine Images (AMI)?

Customized EC2 instances that can have their own software, configuration, OS, monitoring, etc.

Will have faster boot / config time since all software is pre-packaged.

Can be launched from a public AMI, your own AMI, or an AWS Marketplace AMI.

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Describe EC2 instance stores

a high-performance hardware disk physically attached to an EC2 instance

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List some pros and cons of using an instance store vs EBS volumes

Instance store pros:

better I/O performance
good for buffers / caches / scratch data / temp content

Cons:

loses it’s data when instance is stopped (ephemeral)
risk of data loss if hardware fails
backups and replication are your responsibility

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Describe EBS gp2/gp3 general purpose SSDs

cost effective storage, low-latency
system boot volumes, virtual desktops, dev and test env
1-16 TB

gp3

3k iops and throughput of 125 mb/s
to 16k iops and throughput of 1000 mb/s

gp2

older version of gp3
the size of volume and iops are linked

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Describe EBS provisioned IOPS (PIOPS) SSD (io1/io2)

For critical business apps that require sustained IOPS performance, or those that need more than 16k IOPS

Great for database workloads (sensitive to storage perf and consistency)

io1 - 64k IOPS for nitro, otherwise 32k

io2 block express - sub-ms latency and 256k max IOPS

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Describe EBS hard disk drives (st1, sc1)

can’t be a boot volume
125mb to 16tb

st1 - throughput optimized

max 500 IOPS, max throughput 500mb/s
good for data warehouses, big data, log processing

sc1 - cold storage

max 250 IOPS, max throughput 250mb/s
best for infrequently accessed data
where low cost is important

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True or False

EBS multi-attach is within the io1/io2 family of EBS storage.

True.

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What does EBS multi attach allow you to do?

Attach the same EBS volume to multiple EC2 instances within the same AZ.

Each instance will have full read write permissions, and must use file system that is cluster aware.

Best for:

higher application availability in clustered Linux applications
apps must be able to manage concurrent write operation

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What data is encrypted on an EBS encrypted volume?

All is encrypted:

data at rest
in flight data moving between instance and volume
all snapshots
all volumes created from snapshot

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True or False

Encrypting an EBS volume has a high impact on latency.

False. Using EBS encryption has minimal impact on latency.

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EBS encryption leverages keys from where?

KMS (AES-256)

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How to encrypt and unencrypted EBS volume?

create an EBS snapshot
create a new encrypted EBS volume from the snapshot
attach the encrypted volume to the original instance

What does EBS stand for?

Elastic Block Store

What does EFS stand for?

Elastic File System

What is elastic file system?

Managed network file system that can be mounted to many EC2 instances.

Works with EC2 instances in multi-AZ.

highly available, scalable, expensive, pay per use

What protocol does EFS use?

NFSv4.1 protocol

True or False

EFS is only compatible with Linux based AMI.

True.

What must you use to access the EFS file system?

security groups

Describe the 2 EFS performance modes

general purpose (default), great for latency-sensitive use cases like web servers, CMS, etc.
max i/o - higher latency, highly parallel, good for big data, media processing

Describe the 2 EFS throughput modes

bursting - scales with file system size

2. provisioned - set your throughput regardless of storage size

Describe storage tiers in EFS

For lifecycle management 1. standard for frequently access files, 2. infrequent access for other files, lower price to store

EFS vs EBS vs Instance Store

You have just terminated an EC2 instance in us-east-1a, and its attached EBS volume is now available. Your teammate tries to attach it to an EC2 instance in us-east-1b but he can't. What is a possible cause for this?

EBS Volumes are created for a specific AZ. It is possible to migrate them between different AZs using EBS Snapshots.

You have launched an EC2 instance with two EBS volumes, Root volume type and the other EBS volume type to store the data. A month later you are planning to terminate the EC2 instance. What's the default behavior that will happen to each EBS volume?

By default, the Root volume type will be deleted as its "Delete On Termination" attribute checked by default. Any other EBS volume types will not be deleted as its "Delete On Termination" attribute disabled by default.

True or False You can use an AMI in N.Virginia Region us-east-1 to launch an EC2 instance in any AWS Region.

False. AMIs are built for a specific AWS Region, they're unique for each AWS Region. You can't launch an EC2 instance using an AMI in another AWS Region, but you can copy the AMI to the target AWS Region and then use it to create your EC2 instances.

Which EBS volume types can be used as boot volumes when you create EC2 instances?

gp2, gp3, io1, io2, and Magnetic (Standard).

What is EBS Multi-Attach?

Using EBS Multi-Attach, you can attach the same EBS volume to multiple EC2 instances in the same AZ. Each EC2 instance has full read/write permissions.

You would like to encrypt an unencrypted EBS volume attached to your EC2 instance. What should you do?

Create an EBS snapshot of your EBS volume. Copy the snapshot and tick the option to encrypt the copied snapshot. Then, use the encrypted snapshot to create a new EBS volume.

You have a fleet of EC2 instances distributes across AZs that process a large data set. What do you recommend to make the same data to be accessible as an NFS drive to all of your EC2 instances?

EFS is a network file system (NFS) that allows you to mount the same file system on EC2 instances that are in different AZs.

You would like to have a high-performance local cache for your application hosted on an EC2 instance. You don't mind losing the cache upon the termination of your EC2 instance. Which storage mechanism do you recommend as a Solutions Architect?

EC2 Instance Store provides the best disk I/O performance.

You are running a high-performance database that requires an IOPS of 310,000 for its underlying storage. What do you recommend?

Use an EC2 instance store. You can run a database on an EC2 instance that uses an Instance Store, but you'll have a problem that the data will be lost if the EC2 instance is stopped (it can be restarted without problems). One solution is that you can set up a replication mechanism on another EC2 instance with an Instance Store to have a standby copy. Another solution is to set up backup mechanisms for your data. It's all up to you how you want to set up your architecture to validate your requirements. In this use case, it's around IOPS, so we have to choose an EC2 Instance Store.