Architectural DecisionsServing the Thundering Herd

Supreet Sethi @djinn

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil- Donald Knuth

Stats

l 28000 requests per minutel Page load of 7s including imagesl 14th most visited site in India

Sizing and planning

lPlan forlnetworkltraffic split on different pageslIOPSlCPU/RAMlUnderstand the beast

Toolset and Services

lMemcachelRedislMCRouterlMessage Queues (AMQP, Kafka)lVarnishlAWS ServiceslCDNslCouchBaselAerospike

All site features are not used equally

Discover services on top of the funnel and optimize first

lJabong funnel viewlHome pagelCatalog PagelProduct pagel80% of traffic gravitates to these pages

Following structured design changes

will optimize key pages on top of the funnel. It will contribute also in speeding other pages by reducing resource consumption.

Speed - relation to funnel

Programming Strategy

lDefine bottlenecklFind candidate solutions

lTest each candidate one at a timelDeploy in productionlRinse and Repeat

Unit Testing

lClear plan to test every piece of platformlSeparating web-handler from business LogiclTesting with and without web-handlersl Abstract Request and Response interfaces very useful

Staging and Deployment

lLog capture on load balancelReplay the logs on staging server for load testlFormal verification of code

Lessons Learnt

lThings will fail.lScale surfaces bugs.l Key to success is understanding what the system is actually doing. Know if your system is in a healthy state or about to crash.l Have a strategy

Lessons Learnt …

lMake it work.lMake it visible.lMake it DevOps.

Supreet Sethi@djinn

Thank You!