Presentation given by Menno van der Sman from Wakoopa at Ams.rb

1. Lessons Learned
while building

2. or...
How To Run Your Big
App on One Server
AndAHalf

3. Menno van der Sman
Developer at Wakoopa
since May 2007

4. Wakoopa is about
software

6. PC Mac
Linux

7. 200
GB

8. Does it scale?

9. Scaling the front is easy

10. Scaling the back is
harder

11. Limits spawn creativity

12. Servers
at Railsmachine
16GB RAM 5GB RAM
8 Cores 4 Cores
dedicated shared
staging archiving
production
database

13. or...
Keeping Your Database
Happy

14. Queuing
processing multiple items at a time
efficient cache update
DelayedJob for anything else

15. Smart queries
UPDATE developers SET active_seconds = active_seconds + ...
INSERT INTO hourly_usage (...) VALUES (...) ON DUPLICATE KEY UPDATE
active_seconds = active_seconds + ..., idle_seconds = idle_seconds + ...
Allows for concurrency

16. Aim for a Small Rowsize
choose a correct datatype
pick the right indexes
sometimes `id` shouldn’t be the PK

17. composite_primary_keys
Allows efficient PK
class HourlyUsage < ActiveRecord::Base
set_primary_keys :user_id, :software_id, :used_at
...
end
Original implementation by Dr Nic
Maintained by Darrin Holst
http://github.com/drnic/composite_primary_keys

18. Archive old data
that’s not frequently used
SELECT ... FROM hourly_usage WHERE used_at < '...' INTO OUTFILE '/path/to/file'
LOAD DATA LOCAL INFILE '/path/to/file' REPLACE INTO TABLE hourly_usage_storage
avoids long locks

19. Alternative solution
Partitioning
CREATE TABLE hourly_usage_storage ( ... )
PARTITION BY RANGE (software_id) (
PARTITION p0 VALUES LESS THAN (...),
PARTITION p1 VALUES LESS THAN (...),
PARTITION p2 VALUES LESS THAN (...),
PARTITION p3 VALUES LESS THAN (...),
....
PARTITION pn VALUES LESS THAN MAXVALUE
);
Makes ‘WHERE software_id = ...’ very fast
Didn’t work for us

20. Other Techologies
Rails 2.3
Apache
Passenger
REE 1.8.7
MySQL 5.0
Memcached
Sphinx
Amazon EC2

21. Our REE settings
#!/bin/sh
RUBY_HEAP_MIN_SLOTS=500000
RUBY_HEAP_SLOTS_INCREMENT=250000
RUBY_HEAP_SLOTS_GROWTH_FACTOR=1
RUBY_GC_MALLOC_LIMIT=50000000
exec "/opt/ruby-enterprise/bin/ruby" "$@"

22. Questions?
or suggestions?