Gear6 and Scaling Website Performance: Caching Session and Profile Data with Memcached

Scaling Website Performance: Caching Session and Profile Data with Memcached Presented by: Joaquín Ruiz – EVP Products Perry Krug – Systems Engineer 14 April 2009

About Gear6 • First and leading provider of scalable Memcached solutions • Enabling high-growth web sites to deliver and scale dynamic high growth applications and content • Memcached contributor on Github and Google Code • Customers are leaders in media, social networking and content aggregation • Privately held; Headquartered in Mountain View, California 2 : Copyright 2009 Gear6 Inc.

The Web Has Changed • It’s Dynamic, It’s Mobile, It’s High Speed » Consumer internet traffic surpassed business traffic in 2008 » Dynamic (Social Aggregation Media) sites/services are the driving web growth (Social, Aggregation, So… • A distributed caching tier has become necessary and ubiquitous » Approximately 70% of websites are Linux-based (typically LAMP/Java) and are not scalable without a distributed caching tier Because… • Without a distributed caching tier you have no good options SCALE VERTICALLY: $$$ It’s very expensive to do this $$$ » ADD LARGE AMOUNTS OF WEB, APP AND DB SERVERS: $$$ OPEX $$$ » MOVE TO A DIFFENT STACK: “No way! No way!” » GET CRUSHED/SLOW RESPONSE TIMES: “It’s gone from bad to worse” » “Digital Consumer – Undermonetized social networks / video / VoIP driving powerful usage growth growth” – Morgan Stanley Tech Research, 5 Nov 2008, Web 2.0 Summit, San Francisco 3 : Copyright 2009 Gear6 Inc.

Web Architecture with No Cache Web / Application Servers MySQL Databases Ad Load Add Load dd d Web / Application Servers MySQL Databases Every request must hit the database servers and/or E t t th d t b d/ re- re-execute on application servers 4 : Copyright 2009 Gear6 Inc.

Memcached to the Rescue • Memcached: a distributed memory object caching system intended for use in speeding up dynamic web applications by alleviating database load • Memcached is an open source project that developed around the need for dynamic web sites to have a distributed caching tier » Technology: Memcached is a generic two stage hashing system (clients and servers). Clients are written for specific application languages. Server is written in C » U cases: HTML MySQL, Session/profile caching Use HTML, M SQL S i/ fil hi • Memcached is de facto solution » 85% of top 20 sites use memcached; 50%+ of top 5k sites uses Memcached » Memcached has client libraries in all major languages » Memcached has application level plug-ins for apps like WordPress and Drupal 5 : Copyright 2009 Gear6 Inc.

Why should I use Memcache? • Enables scale-out of dynamic websites • Faster page loads pg • Allows for efficient use of your database • Can utilize existing network infrastructure • Very flexible – architect for your workload & resources 6 : Copyright 2009 Gear6 Inc.

Web Architecture with Memcached Web / Application Servers Without Memcached MySQL Databases Web / Application Servers With Memcached Perfect for dynamic website Memcached that generate a Memcache Server(s) e cac ed Memcached high load on their hi h l d th i MySQL Memcached database Databases 7 : Copyright 2009 Gear6 Inc.

Challenges of Memcached Challenges: » Many web implementations require lots of memory and lots of servers for memcache: • Ad i i t ti Administration, power, cooling and li d rackspace challenge » No built-in failover or replication » Instances managed individually • Lack of consolidated management and aggregated statistic gathering • Can be challenging to troubleshoot client, service, instance and key relationships Source: “MySQL and memcached” May 2008 seminar 8 : Copyright 2009 Gear6 Inc.

What is a Session? • Al Almost always l tl larger th than 250 b t bytes, and almost dl t always smaller than 5 kilobytes • Read from datastore for every logged in user for every dynamic page load • Written to the datastore for every dynamic page load • Eventually reaped from the database after N minutes of inactivity Credits: “Cache your sessions. Don't piss off your users” by Dormando 9 : Copyright 2009 Gear6 Inc.

Example: Scaling the User Profile • Too many users creates a load on the database • Replicating the database will help this p g p » Will quickly experience DB replication lag Source: “”Scaling and Tuning MySQL.com” Jan 2009 10 : Copyright 2009 Gear6 Inc.

Where do you keep your Sessions? • Bad: Local sessions (on disk or in memory) » Can’t move users Can t » Can’t avoid hotspots » Not fault tolerant • Good: Centralized sessions (in a central database or in-memory) in memor ) » No porting around of session data » No need for sticky sessions » No hot spots Credits: “Scalable Web Architectures” by Cal Henderson 11 : Copyright 2009 Gear6 Inc.

Caching Sessions with Memcached • Common Wisdom: You Don’t » Users will get logged out if anything goes wrong with memcached » Evictions means that people are logged out of your site » If you upgrade memcached, OS, hardware etc., everyone will be logged off » Addi / Adding/removing memcached servers ki k people off site i hd kicks l ff it • BUT the benefit of caching sessions is HUGE » It is VERY FAST - Zero reads or writes to the database … so people do! Credits: “Cache your sessions. Don't piss off your users” by Dormando 12 : Copyright 2009 Gear6 Inc.

Session Caching Options Approach 1: » Memcached / MySQL hybrid ! Run batch/cron jobs to store session data in both database and memcached » Good for smaller sites or sites where it doesn’t matter as much if session data is lost (Gear6 Approach): Approach 2 » Store session in memcached space only » Provide sufficient memory space to eliminate evictions • Leverage flash density to reduce space and costs • Use DRAM to provide low latency » Use server-based replication to eliminate memcached misses b d l l hd 13 : Copyright 2009 Gear6 Inc.

Gear6: Session Caching Customer Case Production Customer Stats: Alexa rank: top 150 worldwide » 10’s of millions of page views per day » 28 million unique users per month in 2008 » Previously used memcached v 1.2.6 to cache sessions » About 120GB of memcache data used » Customer challenges: g » Need to provide very fast access to use profile information in order to present user with appropriate content (based on user ratings) » Customer: rack space limited and cost sensitive » Need to increase administrative efficiency for memcached tier » Memcached reload can take several hours if failure occurs during which DB load is very high and service latency increased 14 : Copyright 2009 Gear6 Inc.

Gear6: Session Caching Customer Case • Without Gear6: Zero High Availability / Redundancy Slower user experience » 4 U rack space » ~800W power consumption 800W » Zero configuration management » Minimal statistics (Cacti) » Cost per Gig = $100 for hardware only » Double everything for redundancy 32GB 32GB 32GB 32GB 15 : Copyright 2009 Gear6 Inc.

Gear6: Session Caching Customer Case • With Gear6: Fully redundant / cache data protection y p » 2 U rack space » ~400W power consumption » Single point for management gp g » Enhanced stream analysis and statistics » Cost per Gig = $70 for entire solution Savings & benefits of Gear6 solution vs. without Gear6: Over $8k/year in power savings » Immediately deployable with no code changes » 1/4th the rack space » Customers immediately presented with high-affinity content based » on profile and rating history p g y » Less expensive to deploy with Gear6 than without! 16 : Copyright 2009 Gear6 Inc.

Gear6 Web Cache Specifications Gear6 Web Cache Software Gear6 Web Cache Module • High memory density & advance memory allocation » Best-in-class hybrid RAM-Flash Best in class RAM Flash configurations » Advanced memory management » Most efficient object eviction implementation Gear6 software delivered on best-of-breed, » High bandwidth support industry standard servers, DRAM and Flash • High availability Module specs: » Rich cluster functionality •1 U rack profile with four flash drive bays » Failover configurations •Minimum of two modules per appliance » Cache replication options •Two power supplies per module • Advanced management •Four bonded GE ports per module » Hot key and client analysis •Two Quad Core processors » Service-wide diagnostics •Up to 300GB per rack unit » Aggregated physical and logical views 17 : Copyright 2009 Gear6 Inc.

Resources • www.gear6.com • Twitter » twitter.com/memcached • Github » http://github.com/zyounker/brutis/tree/master p //g /y / / / » http://github.com/rama/statsproxy/tree/master • Google code » http://code.google.com/p/brutis/wiki/Readme » http://code.google.com/p/statsproxy/ 18 : Copyright 2009 Gear6 Inc.

April 14, 2009 Webinar Poll Results If you do use memcached, do you use it for: None of the above 0% All of the above 8% Session and profile caching 0% Caching HTML web pages 42% MySQL or other data caching 67% What client are you using for memcached? Other 44% Perl 0% Java Based 11% PHP 44% 19 : Copyright 2009 Gear6 Inc.

Questions? Thank you for attending “Scaling Website Performance: Caching Session and Profile D P fil Data with Memcached” ihM h d” presented by Gear6 Joaquin Ruiz Gear6 salesinfo@gear6.com +1 650 587 7116 20 : Copyright 2009 Gear6 Inc.

Gear6 and Scaling Website Performance: Caching Session and Profile Data with Memcached

by Gear6 on Apr 17, 2009

Accessibility

Categories

Tags

Upload Details

Usage Rights

2 Embeds 9

Statistics

Gear6 and Scaling Website Performance: Caching Session and Profile Data with Memcached — Presentation Transcript

http://www.slideshare.net	8
http://www.gear6.com	1