This document discusses using solid state drives (SSDs) to address the database scale out problem for a growing website. It summarizes the challenges of keeping site performance high while data and traffic increase. Traditional approaches like replication and query optimization were no longer sufficient. Testing Fusion-io SSDs on HP Blade servers showed dramatic improvements in queries per second, response times, replication catch-up times, and server recovery times compared to SAS HDDs. SSDs allowed scaling the database infrastructure on fewer servers, reducing operating costs by 75% while improving performance and scalability. Other potential uses of SSDs in the data center are also mentioned.

1. Answering the Database Scale Out Problem:
SSDs in the Data Center
April 14, 2010
Dan Marriott
Director - Production Operations
danm@answers.com

2. Database layer
• MySQL 5.0.87-b20-percona
• MySQL 5.0.51a
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3. Challenges
• Keep site fast
 while site traffic and stored data are ever-increasing
• Replication lag = 0
 or users get stale data
• Forever being forced to further optimize queries
 constantly vying for dev resources to do this
• Controlling hardware growth (Cap & OpEx $$$)
 regularly adding servers to handle growth
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4. Handling high growth – database tier
• Separate reads and writes
• Add more read DB slaves
• Use Memcached where possible
• Optimize Queries
• Partition large databases
_________
Started hitting a wall: Replication Lag even
when servers handling modest # queries/sec
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5. Typical DB read cluster
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6. Fusion-io for HP Blade Servers
• March ’09: HP announce IO Accelerator card for
blades (manuf. by Fusion-io)
• Sizes:
 80 & 160GB SLC
 320GB MLC
• April ’09: received two cards – began testing
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7. Easy to install
• One man job. Takes 60 secs.
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8. Performance Tests
Blade Server – Blade Server –
Test SAS HDDs Fusion-io card Improvement
Max Queries/sec
(Seconds_Behind_Master: 0)
350 Q/sec 3,500 Q/sec 900%
Application response
100 ms 70 ms 30%
time
Replication catch-up
> 6 hours 12½ mins 3,000%
time (after restore)
Full DB server
> 8 hours 55 mins 800%
recovery
Additionally, CPU load dropped from 30% to 18%
(even with Fusion-io driver overhead)
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9. Typical DB read cluster
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10. Fusion-io Value Add for Answers.com
• Scalability. >Twice the performance capacity on
1/4 servers
• 100% ROI on day of purchase (repurpose other 3/4)
• 75% reduction in operating costs:
 Rack Space, Power and Cooling
 Server Administration
 Database Administration
• 75% fewer failure points
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11. Other SSD uses in the Data Center
• Varnish (Web caching layer)
• DB Backup Servers
• Log Analysis
• Data Warehouse
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12. Thank you.
Slideshow: http://tinyurl.com/mysqlconf2010-ssd-dan
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