EC2 Instance Types: What are they and which one should you use?

Back in 2010, Amazon Web Services (AWS) launched the t1.micro instance type. They followed this up with the first of the T2 instances (micro, small, and medium) in 2014, more sizes in 2015 and 2016, and finally unlimited bursting. Then, in 2018, AWS launched Amazon EC2 T3 (Elastic Compute Cloud). This was augmented in early 2019 with a less expensive variant – the T3a. T3 and T3a were more cost-effective than their forerunners, providing AWS users with general-purpose, burstable instances.

AWS EC2 T3 instances provide users with computing, network resources, and memory that are completely balanced. They also give users a CPU performance baseline and can burst beyond their threshold when needed.

T3 instances require next-gen hardware to run, ideally with custom 2.5 GHz Intel Xeon Scalable (Skylake) processors. When run using optimal configurations and hardware, AWS EC2 T3 instances can give users next-level performance and efficiency. T3 instances are available in seven sizes:

When is the best time to transfer workloads to Amazon EC2 T3 instances?

The introduction of burstable T3 instances types further encouraged users to run workloads even when these do not need prolonged, high-level CPU performance.  This presents users with a tricky situation and may place them in a tight spot if used excessively. Just because you’re using AWS infrastructure doesn’t mean everything’s optimized. By default, T3 instances don’t have limits. But continuously deploying T3 instances can incur huge costs, especially when running highly demanding workloads.

Opsani can help users determine when to move workloads to T3 instances. Leveraging its AI-fueled cloud optimization engine, Opsani looks deep into every workload and thoroughly analyzes its requirements. The software then decides whether a workload is best to run on an AWS EC2 T3 instance or if it’s more viable to go with R5, M5, C5, or other instance families. Simply put, Opsani delivers true AWS optimization, even with AWS’s latest T3 instances product offering.

With Opsani’s combined experience and expertise in cloud optimization, available services, and configurations on both on-premise and public cloud infrastructure, coupled with their patented AI-driven optimization engine, users get the most knowledgeable answer as to when or where to place their workloads and apps.

When To Use AWS EC2 T3 Instances: Factors To Consider

Nitro systems power T3 instances and support network and EBS bursting. You need to keep a close eye on things like HVM virtualization and the need to start inside a virtual private cloud (VPC) that uses an AMI, which comes with the elastic network adapter (ENA) driver.

Opsani’s powerful optimization engine takes in metadata from AWS, performs complete and thorough checks on workloads and their requirements, and compares your workloads’ needs against the capabilities of various types of cloud instances. Our team of performance optimization experts works to determine that only suitable workloads are categorized as migration candidates for T3. Other considerations are pointed out and manifested to our users.

Comparing Costs of T3 vs T2, M5, & R5 Instances

Assuming the following conditions are true:

  1. Instances functioning @ 100% for a 1-month period
  2. T3.xlarge baseline performance is 1.6 vCPUs (40% * 4 vCPUs)
  3. T2.xlarge  Baseline performance is 0.9 vCPUs (22.5% * 4 vCPUs)
  4. Extra charges of $0.05 (for Linux) and $0.096 (for Windows) per vCPU-hour for T2/T3 bursting beyond credits

Finding Breakeven Points for Amazon EC2 T3 Instances

Below is a breakdown of the break-even point for the amount of time a T3 unlimited can run at 100% CPU against the equivalent M5.

  • For Linux

($138-$120)/(0.05*2.4) = 21% of the time or 150 hours out of the month

  • For Windows

($271-$173)/(0.096*2.4) = 59% of the time or 425 hours out of the month

Crucial Insights Into Running Workloads on AWS T3s Against Other Instance Types

Amazon EC2 delivers a vast selection of instance families and types to choose between. These guidelines help you determine the best choice for your T3-compatible workload:

  • If you can fit on less CPUs, R5 offers the best value
  • A T3 unlimited running @ 100% is 25-50% more expensive than the equivalent M5 – the additional costs for unlimited bursting can be consequential
  • T3 instances are unlimited by default, causing customers to gain considerable charges when left unchecked
  • Opsani recognizes when unlimited bursting charges go beyond the threshold – e.g. breakeven point with M5 costs. The software will suggest using a different instance type or deactivating “unlimited” mode (e.g. dev/test workload)
  • T3 offers better value than T2, including extra CPU credits and better baseline performance, faster CPUs. The downside is the migration effort.
  • The cost difference of the instance types between Windows and Linux is considerable and results in different optimal instance types:
  • For Linux, T3 is priced lower than T2. But for Windows, T3 is a tad pricier than T2.
  • The breakeven point for unlimited bursting of T3 vs M5 instances is greatly diminished on Linux as opposed to Windows (21% vs 59%)

These last few paragraphs have shared some, but not all of the considerations when choosing the right instance type.  Is my workload best served by an instance that is burstable? Can I put limits on bursting without negative or at least acceptable effects on my application?  Are the assumptions I am basing my decision on likely to be correct and constant? Opsani’s AI not only evaluates these considerations, but because it is able to learn based on application behavior over time,   Opsani can continuously tune the system performance with much less effort than doing this through a manual approach. 

Considerations for EC2 Reserved Instances (RI)

Reserved instances can provide substantial cost savings, but also, even with a RI marketplace that allows resale of RIs, a certain amount of lockin. Having T2 or even T3 instances and realizing that a T3a would be more cost-effective can leave one feeling buyer’s remorse. The good news is that the Opsani’s team of optimization professionals is ready to help you leverage your existing reserved instances as well as plan and implement a comprehensive RI acquisition strategy to get most out of your current RIs. While selling a RI on the AWS marketplace might be a solution, converting instances within an instance category can result in improved performance and cost savings. Moving four T3.small instances to a T3.large might be a more efficient option and Opsani can help identify these sorts of optimizations. We at Opsani will be with you step by step to ensure your infrastructure achieves the optimal state, and to prevent the purchase of long-term reservations for older instance types that you can’t convert.

Match Candidate Workloads to T3s Automatically

Opsani’s robust AI-driven optimization engine plus the team’s experience and expertise in cloud optimization, available services, and configurations on both on-premise and public cloud infrastructure can help you immediately find and move workloads suited to take advantage of the efficiency and cost savings offered by T3 instances.