Download - Stack Exchange Infrastructure - LISA 14
The Stack Exchange
InfrastructureVroom Vroom
inet.perf.profile
• SRE Generalist @ Stack Exchange
• @GABeech
• http://brokenhaze.com
• http://stackexchange.com
A brief Overview
• 560 Million Page Views a Month
• 34TB of Data transfered a Month
• 1665 rps (2250 peak) Across web Farm
• WISC(HER)
Our First Priority is
PerformanceNobody likes a slow site, least of all us.
When your site is slow people leave.
Make your site fast, and the people will stay
Good write up on moz.com:
http://moz.com/blog/site-speed-are-you-fast-
does-it-matter
The Performance
toolkit
• Mini Profiler
• OpServer
(https://github.com/opserver/Opserver)
• Client Timings
(http://teststackoverflow.com/)
Mini Profiler
OpServer
OpServer HAproxy
OpServer Redis
OpServer SQL
Client Timings
You can’t be fast if
you are not up
• Highly Redundant network
• Datacenter, ISP, Edge, Core, Server,
Port
Load Balencers
• HAProxy
• 2 Servers (Hot/Standby)
• Multiple Tiers (HAProxy Processes)
SSL Termination
• Terminated at LB
• Feature added to HAProxy 1.5
• See:
http://brokenhaze.com/blog/2014/03/25/
how-stack-exchange-gets-the-most-out-
of-haproxy/
Web Servers
• IIS
• 9 Production (2 Test/Dev)
• Dell R610’s
• 32GB Memory
• 2xE5-5640
Data Tier
• MS SQL Server
• 4 Servers
• 2 Always-On Clusters
• Each Cluster 1 RW, 1 RO
Caching Tier
• Redis
• 2 Servers
• Hot / Standby configuration
Tag Engine
• Our Special index of SO
• Tagging is hard
• Written by Marc Gravell
• http://blog.marcgravell.com/2014/04/technica
l-debt-case-study-tags.html
Elastic Search
• 203GB Index
• 3 Machines
• 42M searches/day
Deployment
• Git
• TeamCity
• Custom Powershell Scripts
So what does this get
you
• 52 ms homepage render time
• 33 ms questions page render time
Always See our
Performance
• http://stackexchange.com/performance
Thank YOU!
Contact:
@GABeech
Office Hours:
Wednesday, November 12th
(today…)
2:00pm - 3:30pmLISA Lab