Sam GhodsVP Technology

The simplest way for businesses to share and access data, anywhere

12 months ago…

400M files40M folders

One MySQL database

Need to scale!

NoSQL!

“NoSQL” goodies

• Easy to scale– Just add machines!– Sharding handled by the database– Linearly scales, shared-nothing, no serious SPOF

• Fast, fairly simple CRUD operations• Schema-less

Not so fast.

We sharded MySQL instead.

Why???

If you use a NoSQL store, but need any advanced features in your data

store, you have to rebuild them from scratch yourself.

If you are willing to partition your data yourself, you can use

MySQL’s fancy features.

Inter-Row Consistency

Inter-Row ConsistencyFile trees must remain consistent

• Folder A– Test File– Test File

• Solution: unique index• Solution: lock folder A

Inter-Row ConsistencyModify data structure and log event

• Folder A– Test File 1

Inter-Row ConsistencyModify data structure and log event

• Folder A– Test File 2

• Solution: Use transactions rename event

Inter-Row ConsistencyDenormalizations

• Folder A– Test File 1

• Solution: transactions

delete this must be deleted too

Indexes

• Indexes are way more awesome than people give them credit for– Guaranteed to be consistent– Extremely fast– Data locality – Only access and pull the data you

need– No maintenance required except initial ALTER cost

• SELECT files ORDER BY name (or updated time, or size, etc…)

Tools

• How do you know what’s happening in your data store?– SHOW FULL PROCESSLIST– innotop

• Benchmarking tools– mysqlslap

• pt-query-digest– github.com/box/anemometer

Maturity/Reliability

• Biggest companies in the world have been using MySQL for primary data storage for over a decade– Facebook, Google, Twitter, every other

company ever• When you’re dealing with the crown jewels

of your company, you can’t experiment

HBase!

HBase

• Currently using it as a massive event-propagation store (which can be recreated from MySQL data)

• Started a 3-person task force to learn and productionalize it

• Considering moving more to it in the future but likely need few more years of production experience

Final Thoughts

• Don’t choose a database just because “it scales”

• “Wade, don’t jump into new technologies.”• If you go with new technology, be aware that

crazy things might happen• Make sure you’re not rebuilding MySQL

Hiring!sam@box.com