Memcached

Memcached is a high-performance, distributed memory object caching system, designed to speed up dynamic web applications by alleviating database load, as seen in YouTube, Reddit, and Twitter. It was originally developed by Danga Interactive and is now used by many companies, including Facebook, Amazon, and Google. Memcached is often used in conjunction with other technologies, such as MySQL, Apache HTTP Server, and PHP, to improve the performance and scalability of web applications, as demonstrated by Yahoo! and eBay. The system has been widely adopted and is considered a key component of many modern web architectures, including those used by LinkedIn, Pinterest, and Instagram.

Introduction

Memcached is a distributed memory caching system that stores data in RAM to reduce the number of database queries, as used by Wikipedia and Flickr. It is designed to be highly scalable and can handle a large number of concurrent requests, making it suitable for use in high-traffic web applications, such as those used by Netflix, Dropbox, and Airbnb. Memcached is often used in conjunction with other caching technologies, such as Squid and Varnish Cache, to provide a multi-layered caching system, as seen in The New York Times and The Guardian. The system is also compatible with a wide range of programming languages, including Java, Python, and Ruby on Rails, making it a popular choice among developers, including those at Microsoft, IBM, and Oracle Corporation.

History

Memcached was first developed in 2003 by Brad Fitzpatrick, the founder of Danga Interactive, as a solution to the performance problems faced by LiveJournal, a popular blogging platform, which was also used by Six Apart and Moveable Type. The system was initially designed to be a simple, distributed memory caching system that could be used to store and retrieve data quickly, as needed by TypePad and Vox. Over time, Memcached has evolved to become a highly scalable and feature-rich caching system, with contributions from many developers, including those from Google, Facebook, and Twitter. Today, Memcached is widely used by many companies, including Amazon Web Services, Rackspace, and Salesforce.com, to improve the performance and scalability of their web applications, as well as by NASA, MIT, and Stanford University.

Architecture

Memcached is designed as a distributed system, consisting of multiple cache servers that store and retrieve data, as used by Cisco Systems and Juniper Networks. Each cache server is responsible for storing a portion of the overall cache, and data is distributed across multiple servers using a hashing algorithm, similar to those used by Akamai Technologies and Level 3 Communications. This allows Memcached to scale horizontally, adding more cache servers as needed to handle increased traffic, as seen in Black Friday (shopping). The system also includes a number of features, such as load balancing and failover, to ensure high availability and reliability, as required by Visa Inc. and Mastercard.

Features

Memcached includes a number of features that make it a popular choice among developers, including expiration times, cache invalidation, and statistics collection, as used by Adobe Systems and Autodesk. The system also supports a number of protocols, including TCP and UDP, and can be used with a wide range of programming languages, including C++, JavaScript, and Perl, as seen in Apache HTTP Server and Nginx. Additionally, Memcached includes a number of tools and utilities, such as memcached-tool and memcache-top, to help administrators manage and monitor the cache, as used by Red Hat and Canonical Ltd..

Use_cases

Memcached is commonly used in a variety of scenarios, including web application acceleration, database query caching, and content delivery networks, as seen in CNN and BBC News. The system is particularly well-suited for use in high-traffic web applications, such as social media and e-commerce sites, where it can help to reduce the load on databases and improve response times, as demonstrated by eBay and Amazon. Memcached is also used by many cloud computing providers, including Amazon Web Services and Microsoft Azure, to provide a scalable and highly available caching solution, as required by Salesforce.com and Dropbox.

Security_considerations

Memcached includes a number of security features, such as authentication and authorization, to help protect the cache from unauthorized access, as used by Banks and Financial institutions. The system also supports encryption and SSL/TLS, to ensure that data is transmitted securely, as required by PCI-DSS and HIPAA. However, Memcached is not immune to security threats, and administrators must take steps to secure the cache, such as using firewalls and access control lists, as recommended by NSA and NIST. Additionally, Memcached can be vulnerable to denial-of-service attacks, and administrators must take steps to mitigate these risks, such as using rate limiting and IP blocking, as seen in Cybersecurity and Information security. Category:Free software