cache.t2.medium (Amazon ElastiCache Instance Overview)

Use Cases for cache.t2.medium

Primary Use Cases

• Development and Testing Environments: The moderate resources, combined with burstable performance, make the cache.t2.medium instance type ideal for development teams needing performance spikes for testing but typically low day-to-day usage.

• Small to Medium Real-Time Analytics: Lightweight applications that require caching for moderate data sets, small-scale eCommerce stores, or mid-sized blogging websites can leverage t2.medium for elastic caching support.

• Session Storage: Suitable for environments needing a simple in-memory storage layer for user sessions without constantly high demand for processing.

• Caching API Responses: When used for throttled APIs that do not have constantly high call volumes, cache.t2.medium can provide cost-effective caching as occasional peaks occur.

When to Use cache.t2.medium

• Low-to-Moderate Workload Usage: Applications with consistent low resource use but occasional peaks can benefit from the burstable nature of the t2.medium instance.

• Budget-Conscious Teams: This instance type offers a balance of cost-saving and performance and is recommended for startups, small businesses, or financial-limited projects where cost is a primary constraint.

• Elastic and Part-Time Web Applications: Hosting applications that operate part-time or have intermittent demand, such as morning newsletters or processing daily reports in non-peak hours.

When Not to Use cache.t2.medium

• Continuous High CPU Demand: If the workload requires heavy or consistent CPU utilization, a compute-optimized instance like cache.c5.large or an m-series alternative is a better choice as t2.medium can quickly run out of CPU credits in the case of sustained high loads.

• High-Throughput Workloads: These workloads, such as high-request volume gaming backends or large data processing applications, would better suit the m-series or r-series for improved throughput and memory capacity.

• Real-Time Analytics with Large Datasets: While t2.medium can handle some light real-time analytics, large datasets that scale beyond 3.22 GiB of RAM and demand high I/O will need instances like r5.large, which provides better memory performance.

Understanding the t2 Series

Overview of the Series

The t2 series is part of the general-purpose burstable performance category in Amazon ElastiCache, providing baseline performance along with the ability to burst to higher performance when needed. This series is well-suited for workloads requiring occasional high CPU performance, but that primarily remain idle or underutilized for significant periods of time. The t2 series was designed to offer cost-effective options for smaller and moderate workloads with predictable performance needs.

Key Improvements Over Previous Generations

Introduced as a burstable instance line, the t2 series boasts several improvements when compared to previous instance families:

• Credit-based CPU model: Offers baseline CPU performance with "CPU credits" that accumulate when the instance is underutilized, and are used when performance spikes.
• Efficient cost structure: Designed to be a cost-effective solution for workloads with intermittent or regular but infrequent usage spikes.
• Broad compatibility with open-source caching engines for use with Redis and Memcached caching workloads.

Comparative Analysis

• Primary Comparison:

  Within the t2 series, the cache.t2.medium offers moderate capacity with 2 vCPUs and 3.22 GiB of memory, making it suitable for smaller scaling tasks, while maintaining flexibility for burstable performance. It sits between the smaller t2.micro and larger instances like t2.large, enabling users to balance performance and resources for their specific use cases.

• Brief Comparison with Relevant Series:

  • General-Purpose Series (e.g., m-series): Unlike the m-series, which offers consistent baseline CPU performance across all tasks, the t2 series allows the optimization of costs through its CPU credit model. Choose t2 instances if your application experiences sporadic bursts of activity, while m-series is better for applications that require steady CPU throughout.

  • Compute-Optimized Series (e.g., c-series): For tasks that require continuous and high CPU utilization (such as complex computations, large data processing, or high-demand API serving), the c-series provides better performance than the t2 series, which is more suitable for variable workloads.

  • Cost-Effective Options Like t-Series: The t2 family is a predecessor to the newer t3 series. The t3 series offers additional improvements such as more flexibility in instance sizes, better energy efficiency, and the option for unlimited CPU burst, which can make it a more attractive option for dynamic, modern use cases.

  • Series with Unique Features (e.g., high network bandwidth): Compare with instances like r-series if your application demands high-memory and network throughput for large-scale real-time data processing or in-memory analytics. The t2 series would not be ideal in such scenarios due to its lower throughput and memory constraints.

Migration and Compatibility

If planning to migrate from an older or different generation, load testing is essential to ensure compatibility for specific workloads. The t2 family is compatible with most existing Redis and Memcached engines, but moving to t2 from fixed-performance families like m-series should involve performance testing under typical application loads. It's also important to monitor CPU credit usage after migration to ensure that applications do not exceed CPU limits too frequently, as excessive bursting can lead to degraded performance without CPU credit reserves.