A talk given at the San Francisco Rails Meetup about deployments tips and tricks.

1. @smathieurainforest
Deployment:!
tips and tricks

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Why?
Deployments are scary
Major cause of downtime
Wasted time

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About
@smathieu

5. “We only deploy 20 times per day”

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Tip #1

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Tip #2

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Have a staging server

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Tip #3

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Tip #4

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Deploying Without Downtime

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Migrations
Major challenge to get right
It gets harder with data

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ActiveRecord’s Column Cache

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Don’t delete columns
rename_column :users, :notes, :deprecated_notes
_2014_01_01

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Adding Indexes
Slows on large tables
Locks the table

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Postgres
CREATE INDEX CONCURRENTLY

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MySQL
Percona Toolkit:
http://www.percona.com/software/percona-toolkit
Facebook’s Online Schema Change:
https://www.facebook.com/notes/mysql-at-
facebook/online-schema-change-for-mysql/
430801045932

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Renaming Columns
Don’t do it

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Tip #5

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Having a staging server is
nice, but…

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… on demand staging is
better

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And many more…

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Conclusion
Your CI should be the only thing deploying your
code
No-Downtime Deployments are harder, but
possible
Invest in your deployment processes

30. rainforest @smathieu
Questions?

31. @smathieurainforest
Links
https://github.com/jipiboily/fourchette
https://www.facebook.com/notes/mysql-at-facebook/online-
schema-change-for-mysql/430801045932
http://www.percona.com/software/percona-toolkit