AWS Certified SysOps Administrator - Associate

Domain 6 Cost and Performance Optimization

EC2 Instance Types and Host Size for Optimal Performance

Welcome to this comprehensive guide on EC2 instance types and host sizing for optimal performance. In this article, we’ll explore the various EC2 instance families, their key performance characteristics, and how to choose the best instance for your workload.


General Purpose Instances

General purpose instances deliver a balanced mix of CPU, memory, and I/O performance. They are ideal for diverse workloads, including web servers, CI/CD systems, and general applications. Typically, these instances feature a baseline configuration of one CPU core per 4 GB of memory. For example, the M series offers consistent performance, while the T series provides burstable CPU capabilities through CPU credits that allow temporary performance spikes.

The image compares two series of general-purpose computing resources: the M Series, which offers a balance of compute, memory, and networking resources, and the T Series, known for burstable performance suitable for workloads requiring occasional CPU bursts.


Compute Optimized Instances

Designed for compute-bound applications, compute optimized instances deliver high-performance processors with a typical ratio of one CPU core per 2 GB of memory. These instances are perfect for scientific modeling, high-performance computing (HPC), and other scenarios where CPU-intensive processing is essential.

The image is about "Compute Optimized" applications, highlighting their suitability for compute-bound tasks and various high-performance computing needs. It includes a graphic of a hand holding a cube and two points detailing specific use cases.


Memory Optimized Instances

Memory optimized instances are tailored for workloads requiring large in-memory datasets, such as in-memory databases, caching, and big data analytics. These instances typically offer one CPU core per 8 GB of memory. The R series is a prominent example, while other series like U, X, and Z provide higher memory capacities for specialized requirements.

The image is a chart categorizing different series of memory-optimized computing instances (R, U, X, and Z Series) with descriptions of their specific use cases, such as databases, big data processing, and high memory applications.

Tip

Always consider using the latest generation instances when possible. For instance, if you observe R4, R5, R6, or R7 in the R series, opting for R8 is typically beneficial if your workload supports it. R8G variants indicate the use of Graviton (ARM-based) processors, while other models may be optimized for Intel or AMD architectures.


Accelerated Computing Instances

Accelerated computing instances are built with one or more GPUs—or specialized hardware like FPGAs—to support machine learning, inference engines, and graphics-intensive applications. They come in a variety of configurations with different memory and CPU ratios, such as:

  • P Series: General-purpose GPU tasks.
  • G Series: Graphics-intensive applications.
  • DL Series: Deep learning tasks.

The image is a diagram of "Accelerated Computing" showing three series: P Series for general-purpose GPU tasks, G Series for graphics-intensive applications, and DL Series optimized for deep learning.

In addition to these, series such as F, INF, VT, and TRN may also be available. It is important to be aware of their existence even if memorizing every detail is not necessary for exam preparation.

The image is a diagram titled "Accelerated Computing," showing four series: F Series, Inf Series, VT Series, and Trn Series, each with a brief description of their specialized functions.


Storage Optimized Instances

Storage optimized instances are designed to meet requirements for high I/O performance and large-scale data storage. They are available in several sub-types:

  • I Series: Engineered for high IOPS and low latency.
  • D Series: Ideal for dense, high-capacity storage.
  • H Series: Optimized for high disk throughput and large storage capacities, commonly used with distributed computing frameworks such as Hadoop or EMR.

The image describes three types of storage-optimized series: I Series for high IOPS and low latency, D Series for dense storage, and H Series for high disk throughput and capacity.


HPC Optimized Instances

HPC (High-Performance Computing) optimized instances are specifically engineered for large-scale simulations, deep learning training, and other intensive computational tasks. Typically prefixed with "HPC", these instances focus on maximizing performance for parallel computing workloads.


Key Instance Characteristics

Below is a comparison of the primary instance families and their typical configurations:

Instance TypeCPU-to-Memory RatioIdeal Use Case
General Purpose1 CPU : 4 GBBalanced workloads, web servers, general apps
Compute Optimized1 CPU : 2 GBCPU-intensive applications and HPC
Memory Optimized1 CPU : 8 GBIn-memory databases, caching, big data analytics
Storage OptimizedVariesHigh I/O performance or large volume storage
Accelerated ComputingVariesMachine learning, graphical processing
HPC OptimizedVariesLarge-scale simulations and parallel computing

Sizing Considerations

EC2 instance sizing ranges from very small configurations (e.g., nano or micro in the T series) to very large configurations (such as 2x large, 4x large, 8x large, up to 32x large). Sizing generally increases in predictable multiples—often factors of two—though there are exceptions.

For stateful applications (such as databases), vertical scaling (upgrading to a larger instance) may be necessary. In contrast, horizontal scaling (distributing the load across multiple instances) is typically preferred for stateless applications. Tools like CloudWatch and Compute Optimizer can help evaluate if your chosen instance size is optimal or excessive.

The image outlines four considerations for size selection: baseline performance, scalability needs, cost efficiency, and performance metrics, each represented by a numbered icon.


Summary

This guide reviewed the various EC2 instance families and their ideal use cases:

  • General Purpose: Offers balanced compute, memory, and I/O for a variety of workloads.
  • Compute Optimized: Best for CPU-intensive tasks due to its lower memory-to-CPU ratio.
  • Memory Optimized: Designed for applications that require a high memory-to-CPU ratio, such as in-memory databases.
  • Storage Optimized: Suitable for workloads needing high disk throughput or extensive storage capacity.
  • Accelerated Computing: Leverages GPUs and other accelerators for machine learning and graphics-heavy tasks.
  • HPC Optimized: Engineered for high-performance parallel computing and extensive simulations.

Final Tip

When selecting an EC2 instance type and size, always align your choice with your workload requirements and performance goals.

This overview should guide you in selecting the appropriate EC2 instances to achieve optimal performance for your applications and operational needs. Happy deploying!

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