cache.t2.small (Amazon ElastiCache Instance Overview)

Use Cases for cache.t2.small

Primary Use Cases

• Low-to-Medium Throughput Applications: Suitable for web applications or platforms where caching is primarily used to reduce database load during medium-traffic periods but which can benefit from periods of higher caching demand.
• Workloads with Variable Traffic: Ideal for workloads like session storage, gaming leaderboards, user profile retrieval, or simple data caching, where the performance requirements occasionally spike.
• Development and Testing Environments: Leverage cache.t2.small for environments where cost-effective caching is needed, such as dev/staging infrastructures where workloads have unpredictable or short bursts of demand.

When to Use cache.t2.small

• Web Applications: For websites with periodic traffic peaks, cache.t2.small provides the flexibility to burst CPU usage while remaining cost-effective during off-peak times.
• Small Caching Layers: Where applications need only a small in-memory cache (512 MiB) to store frequent queries or temporary session data, cache.t2.small balances performance with affordability.
• Startups and Cost-Conscious Projects: It is highly relevant in scenarios where cost is a primary factor, but occasional peaks in demand mean you can't afford performance degradation.

When Not to Use cache.t2.small

• Compute-Heavy Applications: Applications that need constant high CPU utilization, such as advanced analytics, AI-based caching, or real-time calculations, should consider compute-optimized instances (e.g., cache.c5.large) designed for sustained high CPU workloads without relying on burst credits.
• High Memory Requirements: If your application needs more memory than cache.t2.small's 512 MiB, consider moving to instances in the r-series (e.g., cache.r5.large), which provide significantly more in-memory capacity for larger datasets or highly demanding in-memory databases.
• Consistency in Performance: For applications where consistent baseline performance is critical (e.g., finance, large-scale e-commerce), the t2 burst credit system might not be ideal. In these cases, either m5 or r5 instances will provide more stability and eliminate reliance on burst credits for sustained workloads.

Understanding the t2 Series

Overview of the Series

The t2 series is part of Amazon ElastiCache's general-purpose instance types, designed for workloads that have variable CPU usage and require burstable performance capabilities. These instances offer a balance of compute, memory, and network resources, making them ideal for a broad range of caching needs, particularly when performance demands can spike unexpectedly. The t2 instance family operates using a CPU credit system, where instances earn CPU credits when they are underutilized, and these credits can be used to burst performance during periods of higher demand.

Key Improvements Over Previous Generations

• Burst Capability: The t2 series commenced the introduction of burstable performance instances in Amazon ElastiCache. Compared to earlier fixed-performance instance types, the t2 series allows users to handle fluctuating workloads more efficiently by using earned CPU credits.
• Cost Efficiency: The t2 instances, including cache.t2.small, are designed to provide cost-effective caching solutions, with the flexibility to handle transient bursts without needing to provision larger, more costly instances for sustained maximum workloads.

Comparative Analysis

Primary Comparison:

When comparing various sizes within the t2 series, like cache.t2.micro, cache.t2.small, and cache.t2.medium, we mainly observe differences in memory, CPU credits, and network performance. While cache.t2.small provides a good balance for smaller workloads, it falls between cache.t2.micro (smaller-scale workloads and lower memory) and cache.t2.medium, which offers marginally better memory and bursting capabilities.

Brief Comparison with Relevant Series:

• m-Series (General-Purpose): You might want to consider m-series instances, such as cache.m5.large or other m5 instances, when consistent baseline performance per core and more memory are required. The t2 family, though cheaper, isn't ideal for use cases requiring consistent CPU performance.

• c-Series (Compute-Optimized): The c-series (like cache.c5.large) is better suited for workloads that are compute-heavy with minimal memory demand, especially if your application demands sustained high CPU usage—something burstable instances like t2 cannot support reliably over long periods.

• Burstable Performance Series (t-Series): If you're weighing cost-effectiveness and burstable performance, the t-series, including cache.t2.small, is one of the most affordable options. For slightly improved architecture and efficiency, the t3 and t4g families (e.g., cache.t3.small) may offer better sustained performance and slightly lower costs with similar bursting models but need to be considered for their newer processing units.

• Network-Bandwidth Optimized Instances: For use cases that require heavy network traffic, instances in the r-series or m-series typically offer better throughput and higher network bandwidth than the t2 series. These would be more suited for performance-sensitive workloads with consistent network usage needs.

Migration and Compatibility

Migrating from other burstable or smaller instance types within ElastiCache (like cache.t2.micro) to cache.t2.small is straightforward, as it retains the same burstable performance features while offering additional memory and processing headroom. It is generally compatible with most workloads that can tolerate burst-driven performance profiles, as the CPU credit model behaves the same across the t2 family. When upgrading to newer generations, such as t3 or t4g instances, factor in the potential benefits of the Nitro System technology and better cost-to-performance ratios.