JRuby allows running Ruby code on the Java Virtual Machine, providing performance and scalability benefits over traditional Ruby implementations. The document discusses moving a real-world Rails application to JRuby and evaluating different JRuby web servers. It also describes integrating Quartz scheduler to efficiently run frequent background jobs in JRuby.

1. JRuby Everything in a single process Presentation based on moving real world Rails application to JRuby [email_address] ocher

2. Agenda JRuby - pros and cons

3. Reasons to move to JRuby

4. Short JRuby servers description

5. Quartz Scheduler Integration

6. JRuby myths JVM is slow and memory greedy Actually fast and can save a lot of memory! Ruby developers hate Java JRuby can be used in the same way as MRI, without touching Java

7. It's just Ruby on JVM

8. JRuby cons Longer startup times

9. Problems with C extensions Situation gets better

10. JRuby pros JVM – advanced VM

11. Fast Ruby implementation Bright future – invokedynamic (Java 7) No GIL (Global Interpreter Lock) All CPU cores available Mature Java libraries

12. Motivations to move to JRuby SEO application

13. New feature in the App – long time, I/O bound task

14. Tens of concurrent requests

15. Traditional Ruby approach would require many gigabytes of RAM Single request per process (REE with copy-on-write GC support saves only about 30% memory) Java multithreaded servers to the rescue!

16. Available servers Three servers reviewed