varnish and drupal- accelerating website performance and flexibility with varnish cache

Webinar Audio OptionsListen to streaming audio via your computer’s audio– WebEx Audio Broadcast pop-up

Unable to listen via your computer’s audio– Request phone access

Technical support– US & Canada 866-229-3239– International support 408-435-

7088

International phone access numbers: – http://support.webex.com/

support/phone-numbers.html

Introduction

Matt Ackley– Marketing Team– @mbackley

Varnish + DrupalAccelerating Drupal Performance

and Flexibility with Varnish Cache

Varnish + DrupalAccelerating Drupal Performance

and Flexibility with Varnish Cache

Kurt Gray

Hosting Engineer

Acquia Inc.

@kurt

Kristian Lyngstøl

Software Engineer

Varnish Software

@kristian

Matt Ackley

Marketing

Acquia Inc.

@mbackley

Webinar Audio OptionsListen to streaming audio via your computer’s audio

– WebEx Audio Broadcast pop-up

Unable to listen via your computer’s audio

– Request phone access

Technical support– US & Canada 866-229-3239– International support 408-435-

7088

– International phone access numbers: http://support.webex.com/support/phone-numbers.html

Housekeeping

Today’s webinar is being recorded. Slides and recording will be posted in next 48 hours at:

–http://acquia.com/resources/recorded_webinars

Submit questions via Q&A Tab in WebEx, we’ll answer as many as we can

–Give it a try & tell us where you joining from today

Upcoming Events

Cities– New York City, November

9th

– Washington DC, November 18th

– Chicago, November 30th

– San Francisco, December 2nd

Target Audience– Senior IT & Marketing

professionals

Companies Speaking

– New York Stock Exchange

– tmg-emedia (Time Out)

– New York State Senate

– The 451 Group

– Gilbane Group

– VML

– Taunton Press

– Zagat Survey

– Examiner.comRegister at: http://revolution2010.acquia.com/

Recently Recorded Webinars

Client Advisor Webinar - Drupal Staging and Deployment Best Practices

Going from Zero to 60 in Drupal with Acquia

Watch Today at –

http://acquia.com/resources/recorded_webinars

Introduction

Kristian Lyngstol– Varnish Software– @kristian

© 2010 Acquia, Inc.

What is Varnish?

• Reverse proxy cache server• ... and more (load balancer, filter, director, ...)• Open Source (BSD), commercially supported • Typically in front of a LAMP stack:


Example Benchmarks: pages/second

• Typical HA Drupal stack: 200 Drupal pages/minute• ... with Varnish: 2500 Drupal pages/second• ... using smaller backend hardware!


Example Benchmarks: Page latency

• Varnish also improves response times:


Use cases for Varnish

• Typical: Reverse proxy cache in front LAMP stack• As a web request load balancer• ... or behind a load balancer• Behind a CDN• Next to a CDN• As a CDN• With other proxy caches• ...and more!


What does Varnish do?• Caches backend responses, delivers from cache


How does it work?• Varnish stores a cache entry for each Host + URL


What can be cached in Varnish?• Drupal pages for anonymous users• Static content: images, js, css• Other types of static or generated content

What should NOT be cached in Varnish?• Responses to POST requests• Responses with a Set-Cookie: header • User-specific content (logged-in page requests)• Very large media files (> 100MB)• Has a Cache-Control: no-cache header

All cache policies can be tuned using VCL


How long will it be cached in Varnish?• Response header: Cache-Control: max-age=300• If no Cache-Control specified then Varnish uses

the Expires date, if specified • If no Cache-Control or Expires header then

uses Varnish's default TTL, 2 minutes (adjustable)

All cache policies can be tuned using VCL ...


VCL: Varnish Configuration Language• Extend and modify Varnish cache policies• Add behaviors during each phase of delivery: recv, hash, fetch, hit, miss, deliver, ...

sub vcl_recv {

# direct image requests to image servers if (req.url ~ "(jpg|gif|png)") { set req.backend = image_servers; } }


VCL: Varnish Configuration Language• Add/remove/change request or response headers

sub vcl_deliver {

# Add a HIT/MISS header to the response if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; set resp.http.X-Cache-Hits = obj.hits; } else { set resp.http.X-Cache = "MISS"; } }


Other VCL capabilities

• Add/remove/change HTTP headers• Redirects based on request parameters• Rewrite requests• Retry failed requests• Synthesize direct responses • Saint and Grace: Deliver cached content when

backend is unresponsive• ACLs: Network-address filtering• Request filtering• ESI: Separate cache entries and separate cache

policies for each part of a document• Inline C code (eg. redirects based on GeoIP)


Varnish realtime tools

• varnishstat: realtime status and performance metrics



• varnishhist: live frequency plot of response times



• Varnish CLI: live admin capabilities



• varnishtop: live list of hottest files



• varnishtop: analyze incoming HTTP headers

Introduction

Kurt Gray– Hosting Engineer– @kurt


Varnish and Drupal: Cache variances

• Drupal emits Vary: Cookie,Accept-Encoding• Cookie: Avoids cache collisions between users• Accept-Encoding: maintain separate cache

entries for compressed content (gzip, deflate) vs. uncompressed content


Varnish and Drupal: VCL snippets

sub vcl_recv {

# Normalize the Accept-Encoding header if (req.http.Accept-Encoding) { if (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } elsif (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { # unkown algorithm remove req.http.Accept-Encoding; } } }



sub vcl_recv {

# Don't check cache for logged-in users if(req.http.cookie ~ "SESS") { return(pass); }

# Cookie Bypass module: Don't check cache for anon # user who POSTed content less than 10 minutes ago. if(req.http.cookie ~ "NO_CACHE") { return(pass); } }



sub vcl_recv {

# Don't check cache for GET /cron.php if(req.url ~ "^/cron.php") { return(pass); } }



sub vcl_fetch {

# Don't cache if response has explicit no-cache headers if (beresp.http.Pragma ~ "no-cache" || beresp.http.Cache-Control ~ "no-cache" || beresp.http.Cache-Control ~ "private") { return(pass); } }


Varnish and Pressflow Drupal, D7

• Pressflow = Drupal w/ many performance tweaks• Allows Varnish to cache and deliver Drupal page

requests for anonymous visitors• ...because Pressflow doesn't emit "lazy sessions" • No SESS cookies for anonymous visitors• Drupal 7 has same key features


Controlling cache expiration times

• Drupal Admin > Performance pageo Agressive or External cachingo Minimum Page Lifetime = max-age

• Active purging: use Drupal Varnish module• Static content: See the mod_expires directives in

Drupal's .htaccess file• If no Cache-Control or Expires headers: Uses

Varnish's default TTL (2 minutes)


Varnish and Acquia Hosting

• All Acquia-hosted sites benefit from Varnish• Pressflow sites on Acquia-hosting get most benefit• Fully managed HA environment: No setup, no fuss• Reduces backend server size requirments• Excellent load test results

Do you love working with Drupal?

If so, Acquia is hiring in North America & Europe:–Engineering & design–Client advisors and consulting–Inside sales

Check out openings athttp://acquia.com/careers

QuestionsFor more information, visit:– http://acquia.com

– http://twitter.com/acquia

– http://twitter.com/drupalgardens

– http://twitter.com/drupalcommons

– http://acquia.com/facebook

Contact us:– [email protected]

– 888.9.ACQUIA

Try Drupal 7 today, for free – Sign up at http://drupalgardens.com

• Sign up for the Drupal Business Summit– http://revolution2010.acquia.com/

Recording of today’s event and slideswill be posted at:

http://acquia.com/resources/recorded_webinars

varnish and drupal- accelerating website performance and flexibility with varnish cache

Technology