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Siege and Beyond:
 An Intro to Benchmarking and Stress Tests WordCamp Vancouver 2015 Mike Schroder (DH-Shredder) WordPress Platform Lead at DreamHost @GetSource -

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Who Am I? • Mike Schroder, a.k.a DH-Shredder,
 a.k.a. @GetSource • Third Culture Kid, enjoy Coffee & Sailing • WordPress 3.9 Co-Lead and Core Contributor • Happy DreamHost Employee

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What will happen if my site hits the reddit front page?

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What if reddit doesn’t matter to me?

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Prove how many users can access your site at one time.

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Load Testing or Stress Testing?

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Load Tests: Will my site run well with the expected amount of users?

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Stress Tests: How many users before the site/infrastructure cracks?

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Are we testing dynamic or cached requests?

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Varnish/Static: ~50ms

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PHP: ~100ms (without stress)

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PHP: ~1500ms (with stress)

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All methods are not equal.

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“Users/minute” does not necessarily mean “real users during a minute”.

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There are many utilities for stress testing.

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Let’s start with Siege.

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You can run cached or dynamic tests.

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It’s used only from the command line.

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It only runs tests from one server.

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Linux: Packages.
 Mac: Homebrew.­‐home/

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Primary configuration (.siegerc)

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To run dynamic tests login-url = POST log=[user]&pwd=[password]&wp-submit=Log+In&

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A list of URLs.

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List format HOST= ${HOST}/ ${HOST}/?feed=rss2 ${HOST}/?p=41 ${HOST}/?feed=rss2 ${HOST}/?p=44 ${HOST}/ ...

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Results Transactions: 712 hits Availability: 100.00 % Elapsed time: 59.12 secs Data transferred: 3.70 MB Response time: 1.23 secs Transaction rate: 12.04 trans/sec Throughput: 0.06 MB/sec Concurrency: 14.75 Successful transactions: 702 Failed transactions: 0 Longest transaction: 8.49 Shortest transaction: 0.20

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Where can I find test content?

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HHVM’s oss-performance is one option.­‐performance/tree/master/targets/wordpress

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To seed from your own content, take a look at your logs, or try:{*:1-­‐52}  

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You can also use sproxy, not to be confused with stunnel.

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However, it has a friendly GUI to run tests and see the results.

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No content

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Single data center, but from a cluster of AWS servers.

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More complex user behavior? Try a service like LoadStorm.

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What kinds of issues will I find?

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How do I debug problems once they’re found?

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Bonus: Your WordPress site runs slowly, and even more slowly as soon as you enable a persistent object-cache. Why?

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Memcached slab size.

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wp_options cleanup.

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Questions? -­‐   -­‐­‐manual/   -­‐­‐home/
 Mike Schroder (DH-Shredder) WordPress Platform Lead at DreamHost @GetSource -