How to Choose AWS Storage

Amazon Web Services provides various storage options each offering high availability and durability. AWS Storage Services are an essential component of cloud offerings and as we rightly say Storage IS the cloud.

The decision to choose among the various storage options available goes a long way in determining the scalability, performance and cost effectiveness of the application and cloud set-up.

Why AWS Storage

• Reduce On-Premise Cost: It saves the secondary site backups and backup cost and also eliminates the maintenance cost associated with storage.
• Capacity planning and Processes: Growing business needs dictate that companies must plan and add storage when necessary and also be very proactive about capacity planning. Fortunately, AWS has an agile way of adding and removing storage and at the same time allowing you to pay for only what you use.

AWS Storage Services

AWS provides different storage options which are suitable for different workloads and use cases:

There are four different categories of Storage: S3, EBS (Elastic Block Storage), Ephemeral (Instance) store, and Glaciers.

1. S3: Amazon S3 provides object level storage and the user can use a web service interface to store and retrieve the data or objects. S3 can be accessed from anywhere on the web. S3 automatically replicates your data to other AZ’s within the same region and provides 11 nines durability and 4 nines availability. This makes the S3 storage an extremely highly available and scalable storage option to store critical data.

   Amazon S3 objects are files stored in what we call Buckets. Objects can be up to 5 TB and can contain any kind of data. S3 offers several storage classes based on different user cases and objects also have lifecycle management policies which can be used to automatically move data between storage classes based on timeframe defined.

   Here are the two ideal use cases for S3 storage: S3 storage primarily for Backups/Archiving for on-premise/cloud data, static web hosting and Disaster Recovery.

2. EC2 (Elastic Cloud Compute) Storage: The next category in the storage is EC2 storage. When an EC2 instance is created from an AMI (Amazon Machine Image) you will get two options to choose the storage: either EBS backed or Instance backed storage.

   EBS: EBS is the Block Level persistent storage for EC2 instances. EBS volume is mountable network attached storage just like hard disk on physical server. We can mount multiple EBS volumes to one EC2 instance but it has to be noted that only one EBS volume can be attached an EC2 instance at a time. Each EBS Volume is automatically replicated within its availability zones therefore providing high availability and durability.

   Amazon provides the ability to take EBS snapshots of EBS volumes and save to S3. EBS Snapshots provides enhanced durability and other benefits like sharing, cloning EBS volumes in different AZ/AWS Account.

   They are further refined into three categories: Magnetic, General Purpose SSD, Provisioned IOPS SSD. They differ based on underlying hardware, performance and cost. So, based on requirements and weighing all the options you need to arrive at a decision that is cost effective and matches the workload performance.

   Ideal use cases are to use EBS volumes primarily for Databases and File systems etc.

3. Ephemeral Storage: Instance store is not persistent storage like EBS but only temporary block storage for EC2 instances. So, if the instance terminates or stops then all the stored data on that instance store is deleted. This instance store storage is unsuitable for critical data and data which cannot be replicated since the data evaporates after the instance is shutdown.

   Ideal use cases her are to use Instance store volumes is to store temporary backups, application cache, logs, any random data etc.

4. Amazon Glacier

   Amazon Glacier is an archival solution designed for long term backup and archival storage. It is durable and extremely low-cost storage with built-in security features where data can exist for months, years and decades. It eliminates the need for capacity planning, data replication and other hardware migrations. Although it is highly available, its retrieval time is very slow usually 5-6 hours but it is very inexpensive when compared to S3. Glacier is not a solution for storing the data that you frequently access or when you want to retrieve the stored data quickly. Glacier supports two types of encryption, SSE of your Data at rest and SSL encryption for the data in transit.

The above lists some of the storage options which AWS provides. We need to decide on multiple factors to choose which storage options work based on data criticality, cost effectiveness, its usage, etc. Among all, security tops the list. While the above options do offer security, S3 offers server-side encryption as well. Customers using their own encryption keys along with AWS encryption options should help its community develop the confidence to move to private cloud by addressing all the concerns surrounding confidentiality.

Another factor is cost effectiveness. Costs involving different EBS Storage classes based on requirements and long-term cost saving measures by following the life cycle management of S3 have many questions surrounding them when it comes to AWS storage. AWS provides tools to answer some of the questions surrounding this. Simple Monthly calculator (https://calculator.s3.amazonaws.com/index.html) is the AWS tool which helps to provide an estimate based on your specifications and capacity. This is a great tool to start off with and then senior management can do a more deep level analysis.

Hopefully this article has provided enough details about the different storage options that are available in AWS and how to choose the right storage option based on your needs and the uses case.