Apache performance

Apache Web Performance Leveraging Apache to make your site ﬂyFriday, March 16, 12 1

Who am I? & Why would you listen to me?Friday, March 16, 12 2

Devon Hillard Web Application Architect Built 10MinuteMail Run Spark::red, an enterprise eCommerce Hosting company Complex Web Apps with extremely high trafﬁc and critical performance needs devon@sparkred.comFriday, March 16, 12 3Been doing this for 14 years.10MinuteMail handled a Slashdotting, front page listing on YahooTech, and front page Digg at the same time.Worked on sites such as AT&T.com, People’s Choice Awards, PaylessShoes, Vermont Country Store.

What is Performance?Friday, March 16, 12 4

Server-Side Performance • Trafﬁc Capacity • Request handling speed • Request handling throughput • Lower CPU/memory/ bandwidth usage • ScalabilityFriday, March 16, 12 5

Client-Side Performance • Page Load Time • First draw • Inter-actable • Complete • Page Interaction Responsiveness • Time to Complete Use CaseFriday, March 16, 12 6When a user sees the page start loading, to when they can do stuff,to when the browser’s loading animation is done.Use Ajax to pre-populate ﬁelds, type-ahead, real-time ﬁeldvalidation, reduce the number of full page submits/requests.Solving for client side performance can have a dramatic impact onthe server side performance. Cached assets draw pages faster ANDreduce requests the server has to handle.

These two are TIED • Browser caching of static assets reduces page load time AND reduces the number of requests the server has to handle for the same number of page views • AJAX requests can typically be handled with far fewer resources than full page requests • Reduced asset sizes means less bandwidth used and shorter request response sending times • Solving for the Client brings Server performance gains!Friday, March 16, 12 7In engine building they say “Build for torque and the horsepower willfollow”

Why Should I Care?Friday, March 16, 12 8

Everyone Wins! • Client-Side Performance means • happier users • increased conversions • increased SEO ranking • Server-Side Performance means • more capacity on same hardware • saves money • scaling is easierFriday, March 16, 12 9

Increased Conversions • +100 ms of page load time = 1% drop in sales • +500 ms of page load time = 20% drop in searches • +400 ms of page load time = 5-9% increase in clicking “back” button before the page ﬁnished loadingFriday, March 16, 12 10We’ve all seen these stats, but they’re worth repeating. This isn’tivory tower stuff, this is simple business.

Why Apache?Friday, March 16, 12 11

Why I Use Apache • Popular web server - it’s everywhere • Easy to install, troubleshoot, and ﬁnd information on • Mature and stable • Lots of extensions • Enterprise support requirements • It Is fast enough to max out your hardware!Friday, March 16, 12 12Why not nginx (engine-X), Lighttpd, etc...?Extensions like mod_pagespeed, mod_cluster, and more.

CPU Util @ 930 Mbit/sec http://www.webperformance.com/load-testing/blog/2011/11/what-is-the-fastest-webserver/Friday, March 16, 12 13

iftop output - 613 Mbit/sec PCA Awards • Saw 4x the planned for traffic during spikes • 140,000+ pages/minute - 2,333 pps (2012) • 3,000+ Mbit/sec (2011) • 1,200+ Mbit/sec PLUS Akamai CDN offloaded traffic (2012) • The site stayed up and was quick to load and responsive to interact with the whole timeFriday, March 16, 12 14

PuppiesFriday, March 16, 12 15

Basic Apache ConﬁgsFriday, March 16, 12 16The problem with Apache conﬁgs are that the defaults are typicallyextremely out of date and based on much older hardware, networkbandwidth, browser abilities, and application complexity

Every App is DifferentFriday, March 16, 12 17

Which MPM? • Worker MPM scales for high trafﬁc without running out of memory better • Less time spent tuning worker conﬁgs • Unless you’re still using non-threadsafe Apache code (some PHP, etc..) • New in Apache 2.4 is the Event MPMFriday, March 16, 12 18Limited testing I did with Event MPM shows it’s ~5% faster thanWorker, without real tuning.

MPM Worker Conﬁgs Default Mine <IfModule worker.c> <IfModule worker.c> StartServers 2 ThreadLimit 100 MaxClients 150 StartServers 5 MinSpareThreads 25 MaxClients 5500 MaxSpareThreads 75 ServerLimit 200 ThreadsPerChild 25 MinSpareThreads 100 MaxRequestsPerChild 0 MaxSpareThreads 1000 </IfModule> ThreadsPerChild 100 MaxRequestsPerChild 0 </IfModule>Friday, March 16, 12 19Just set it and forget it.If you have memory leak issues, set MaxRequestsPerChild tosomething like 5,000.

ab with small ﬁle Version Apache 2.2.3 MPM Worker Document Size 119 bytes Concurrency Level 1,000 Total Requests 100,000 Requests Per Second 20,790 r/s Throughput 8,077 kb/s hex core X5675Friday, March 16, 12 20

ab with large ﬁle Version Apache 2.2.3 MPM Worker Document Size 95,002 bytes Concurrency Level 1,000 Total Requests 100,000 Requests Per Second 1,258 r/s Throughput 119,966 kb/s hex core X5675Friday, March 16, 12 21

Linux Kernel Conﬁgs net.ipv4.tcp_max_syn_backlog=30000 net.core.netdev_max_backlog=1200 net.ipv4.tcp_timestamps=0 net.ipv4.tcp_sack=0 net.ipv4.tcp_window_scaling=0 net.ipv4.tcp_max_tw_buckets=2000000 net.ipv4.tcp_mem=100000000 100000000 100000000 net.ipv4.tcp_wmem=100000000 100000000 100000000 net.ipv4.tcp_rmem=30000000 30000000 30000000 net.ipv4.ip_conntrack_max = 231072Friday, March 16, 12 22This last setting (or larger) will keep your kernel from droppingincoming connections under high load

Keepalive - On or Off? • reduces overhead of establishing new connections for each request from the browser • can waste memory and other resources if left open too long • Common practice is to disable them • I turn keepalive on, set to 6 seconds or 500 requests • For CDNs like Akamai, you’ll want to turn up the time to more like 120 secondsFriday, March 16, 12 23Defaults are On, 15 seconds (too long), 100 requests (too small)

GZip - mod_deflate • gzip compressing text resources - html, js, xml, css dramatically decreases the size of the response for those assets: often up to 90% reduction in size • reduces transfer time, especially for clients with slower connections (or big files) • This decreases page load time (Client) and reduces the time the server thread is sending the response (Server) # Removing Hosts vary Header unset Vary <IfModule mod_deflate.c> AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css application/x-javascript BrowserMatch ^Mozilla/4 gzip-only-text/html BrowserMatch ^Mozilla/4.0[678] no-gzip BrowserMatch bMSIE !no-gzip !gzip-only-text/html </IfModule>Friday, March 16, 12 24

Browser Caching • Tell the browser to cache all static assets, for as long as you can bear it • Set the ETag • Set cache control and expiration response headers <LocationMatch ^/pca/images/.*> FileETag MTime Size Header set Cache-Control "max-age=2764800, public" <IfModule mod_expires.c> ExpiresActive On ExpiresByType image/jpg A2764800 ExpiresByType image/jpeg A2764800 ExpiresByType image/png A2764800 </IfModule> </LocationMatch>Friday, March 16, 12 25This is HUGE! You can reduce the number of HTTP requests youhave to handle by an order of magnitude or two by setting goodcache headers.

Disk Caching • Why not use mod_mem_cache? • Transparent web server caching of assets reduces load without deployment and development complexities • Some warnings! • Doesn’t auto clean itself • Can grow to be huge if you don’t check the headers being cached • Can grow to be huge if you have dynamic URI content - blah.jpg;jsessionid=foo • Another place to purge cache for changed ﬁlesFriday, March 16, 12 26Mod_mem_cache has some bad bugs. mod_disk_cache lets thekernel’s in memory ﬁle caching algorithm do all the heavy liftingwithout tuning or exhausting available memory.For 3 tier environments, it’s common to have static assets that getdeployed to the web servers separately from the application itself.This makes deployments more complex and error prone and makeslocal dev environments much harder to keep up to date.Seam and richfaces image tags insert jsessionid to URI, etc...

Disk Caching - Conﬁg <IfModule mod_disk_cache.c> CacheRoot /var/cache/mod_disk_cache CacheDirLevels 2 CacheDirLength 1 CacheEnable disk /pca/img CacheEnable disk /pca/ﬂash CacheEnable disk /pca/css CacheEnable disk /pca/js CacheEnable disk /pca/images CacheMaxFileSize 200715200 CacheDefaultExpire 3600 CacheIgnoreHeaders Set-Cookie </IfModule>Friday, March 16, 12 27

Mod_PageSpeed • Open Source Apache Module • Lots and Lots of ﬁlters • image compression • combine js/css • sprite images • domain sharding • etc...Friday, March 16, 12 28I know a previous presentation was done on mod_pagespeed, so Iwon’t dive too deeply into all of it’s features and conﬁgs. Trying tooptimize for performance can make dev more complicated.packtag. pagespeed.

Three Tier • SSL Termination • Load Balancing • Mod_proxy/mod_cluster • Mod_SecurityFriday, March 16, 12 29Apache is key for 3-tier architectures. It provides signiﬁcantperformance, security, and PCI compliance wins.Big improvements in Mod_proxy_balancer with 2.4 (dynamic cluster,session bleedoff, etc)

Building Scalable Clusters w/ Apache • VIP • heartbeat • haproxy • DNS LB • simple round robin • smartFriday, March 16, 12 30

Questions?Friday, March 16, 12 31

Thank you! devon@sparkred.comFriday, March 16, 12 32

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Apache performance

by Devon Hillard on Apr 11, 2012

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Apache performance Document Transcript