Overview
The article discusses the evolution of application data caching from RAM to SSD, highlighting the introduction of EVCache, a distributed in-memory caching solution. It emphasizes the advantages of using SSDs for caching, including cost efficiency and performance improvements.
What You'll Learn
1
How to leverage SSDs for application data caching
2
Why using Memcached External Storage can improve caching performance
3
When to transition from RAM-based caching to SSD-based solutions
Prerequisites & Requirements
- Understanding of caching concepts and distributed systems
- Familiarity with AWS services and EC2 instances(optional)
Key Questions Answered
What are the benefits of using SSDs for caching compared to RAM?
SSDs provide fast access to data at a much lower cost than RAM, allowing for cost-effective storage of large amounts of data without sacrificing availability or performance. The cost to store 1 TB of data on SSD is significantly lower than on RAM, making SSDs a viable option for caching.
How does Memcached External Storage (extstore) enhance caching capabilities?
Memcached External Storage (extstore) allows for efficient data storage on SSDs while keeping metadata in RAM. This approach maximizes storage device utilization and maintains high speed and throughput, addressing performance issues faced with previous caching methods.
What challenges did Netflix face when transitioning from Moneta to extstore?
Netflix encountered performance and throughput issues when overwriting existing data in Moneta due to compactions. These challenges led to exceeding desired SLAs at times, prompting the need for a more efficient solution like extstore that could handle larger workloads effectively.
What is the typical SLA for EVCache and how does it perform under load?
The typical SLA for EVCache is around 1 millisecond with a default timeout of 20 milliseconds, serving approximately 100K requests per second (RPS). During testing, EVCache met its throughput goals with latency rarely exceeding 1 millisecond.
Key Statistics & Figures
Data operations per day
Trillions
EVCache performs trillions of operations daily, showcasing its capacity to handle massive workloads.
Items stored
Hundreds of billions
EVCache has become a fundamental service storing hundreds of billions of items across multiple AWS regions.
IOPS achieved
Over 200K
Using storage optimized EC2 instances, EVCache achieved over 200K IOPS of 1K byte items, meeting throughput goals.
Typical SLA
1 millisecond
EVCache's typical SLA is around 1 millisecond, ensuring fast response times for users.
Technologies & Tools
Some links below are affiliate links. We may earn a commission if you make a purchase.
Backend
Evcache
A distributed in-memory caching solution used for low-latency, high-reliability caching.
Backend
Memcached
An in-memory key-value store used for caching data.
Database
Rocksdb
A key-value store used for storing data on SSD in the EVCache Moneta implementation.
Cloud
AWS
Provides the infrastructure for deploying EVCache across multiple regions.
Storage
Nvme
Used for high-speed data access in SSDs.
Key Actionable Insights
1Transitioning to SSDs for caching can significantly reduce costs while maintaining performance. This shift allows organizations to store larger datasets without the high expenses associated with RAM.As businesses scale, the need for cost-effective solutions becomes critical. Implementing SSDs can provide a balance between performance and budget, especially in cloud environments.
2Utilizing Memcached External Storage can optimize your caching strategy by efficiently managing data storage and retrieval processes.For applications that require high throughput and low latency, extstore can be a game-changer, especially when handling large volumes of data.
3Regularly monitor and analyze read latencies to ensure your caching solution meets performance expectations.Understanding latency patterns can help in fine-tuning your caching strategy and addressing potential bottlenecks before they impact user experience.
Common Pitfalls
1
Over-reliance on RAM for caching can lead to increased costs and scalability issues.
Organizations may face challenges in scaling their caching solutions effectively if they do not consider transitioning to more cost-effective storage options like SSDs.
2
Failing to monitor performance metrics can result in exceeding SLAs and degraded user experience.
Without regular analysis of read latencies and throughput, teams may overlook potential bottlenecks that could impact application performance.
Related Concepts
Distributed Caching Strategies
Cost-effective Data Storage Solutions
Performance Optimization Techniques For Cloud Applications