[samlambert]

Doing this online would of been very tricky while maintaining 100% consistency. We perform major infrastructure changes often without ever having to take the site offline. In this case and at this time it was unavoidable.

I feel 13 minutes of maintenance at 5am PST was a good trade off for the benefits we gained.

[coops]

Can you go into more detail regarding the prohibitive consistency issues? How do you maintain consistency in steady-state (ie. not during migrations?) Also, how do you make the call as to whether to bring your site down vs. attempting a live migration?

[imbriaco]

http://en.wikipedia.org/wiki/Split-brain_(computing)

[coops]

Yes, this is certainly a state you would desire to avoid. However, you didn't answer any of my questions.