cache.t4g.small (Amazon ElastiCache Instance Overview)

Use Cases for cache.t4g.small

Primary Use Cases

• Web session caching: Ideal for caching transient data such as session persistence in web applications, especially those experiencing periodic spikes in traffic.
• Caching layer for low/medium traffic applications: A cost-efficient caching solution for small to medium-sized applications where CPU usage fluctuates.
• Distributed locking: Useful in scenarios where cache instances are used to manage distributed locks in systems that don’t require constant, heavy load processing.
• Data indexing: Great for managing indexing tasks for smaller datasets where periodic bursts of computing power are required to refresh indices.

When to Use cache.t4g.small

The cache.t4g.small instance is best suited for:

• Workloads that are not consistently CPU-intensive but experience occasional bursts of higher CPU usage.
• Newly developed or smaller-scale applications requiring cache performance at minimal cost.
• Distributed web caches perfect for accommodating periods of fluctuating web traffic on demand.
• Projects where price/performance optimization is critical, such as staging environments or startup applications.
• Lightweight caching workloads where cost-saving is more important than consistent high compute or memory metrics.

When Not to Use cache.t4g.small

Consider selecting another instance type if:

• Your caching layer needs consistent heavy CPU or memory usage, in which case the m6g or r6g series could be more appropriate given their steadier performance and resource allotments.
• You require strong memory performance for caching large datasets — in this scenario, the r6g instances (rack-optimized for memory-intensive applications) or high-throughput i-series might be more effective.
• High computational workloads dominate your caching needs, requiring compute-optimized instances like cache.c6g.large.
• Your application’s traffic doesn’t fluctuate significantly, making m6g instances more attractive due to their uniform performance without reliance on a credit model.

Understanding the t4g Series

Overview of the Series

The t4g series is Amazon ElastiCache’s burstable, cost-effective general-purpose instance family powered by AWS Graviton2 processors. Engineered with Amazon’s custom-designed Arm-based Graviton2 chips, the t4g series provides an excellent balance of performance and affordability, making it ideal for workloads that experience variable CPU usage but don't require constant high performance.

These instances offer significant performance improvements at a lower price point compared to earlier x86-based instances. The burstable nature of t4g instances allows them to handle intermittent peaks in resource demands without needing larger, consistently more expensive instance types. They operate under a CPU credit model, where bursts of compute performance can be achieved using accumulated credits.

Key Improvements Over Previous Generations

The t4g series brings several key improvements over its predecessor, the t3 series:

• Graviton2 processors: The introduction of AWS Graviton2 processors provides up to 40% better price/performance when compared to similar x86-based t3 instances.
• Efficiency: Graviton2 chips are also more energy-efficient, consuming less power while delivering higher performance, which leads to cost savings.
• Increased burst capability: More CPU credits are accumulated during idle times, enabling longer and more sustained burst performance.

Comparative Analysis

• Primary Comparison:
  Compared to the older t3 instances, t4g instances offer substantially better performance-per-cost thanks to the Graviton2 architecture. A cache.t4g.small instance will provide the same resource configuration as a cache.t3.small but with better efficiency and compute capability.

• Brief Comparison with Relevant Series:

  • General-purpose (m-series):
    For workloads requiring consistently moderate levels of CPU performance, the m-series such as cache.m6g.large might be a better option. The m-series offers more consistent performance with no CPU credit model, making it ideal for more predictable cache workloads.

  • Compute-optimized (c-series):
    If your workload demands more compute power (e.g., large-scale analytical processing or heavy data manipulation), a compute-optimized instance like the c6g series would be more appropriate. The c-series consistently offers higher levels of CPU performance compared to t-series instances.

  • Burstable performance (t-series):
    The t-series is known for cost efficiency in handling workloads with periodic bursts of high performance, and the t4g-series exemplifies this with its Arm-based architecture. Like its siblings in the t-series, t4g instances excel in cost-effectiveness for general-purpose caches that see intermittent traffic spikes.

  • Specialized features (e.g., high network bandwith):
    For high-memory workloads or those requiring better network throughput, consider instances such as the r6g series. These are optimized for memory-intense operations, or choose network-optimized families for better network bandwidth.

Migration and Compatibility

Migrating to cache.t4g.small from t3 instances is straightforward, but since t4g is powered by Graviton2 (ARM-based architecture), ensure that any custom caching logic or optimizations you’ve included in your application are compatible with the Arm architecture. Testing your Redis or Memcached workload on a smaller t4g instance within a dev/test environment is highly recommended before widespread migration. It’s important to ensure software dependencies (if any exist) are Arm compatible.