Content Addressable

Storagesfor fun and profit.

Berk D. Demir@bddemir

I break and fix things at @StumbleUpon.

Problem.

Serve lots of static assetswith low latency

and high availability.

Understanding data.

A lot.Small.Frequent.

100 million.19 kilobytes.

Updates.

BLOBs don’t change. They get replaced.We want to keep all without duplicating.

Content Addressable

Store

Store immutable content and authoritatively address it with

a cryptographic hash.

We had ideas.

Very bad ideas.

Very bad.Shared Storage, i.e., NFS.

Bad ideas.

Bad.AWS S3, RS Cloud Files, ...

Distributed: AFS, GlusterHDFS (Oh my!)

Bad ideas.Take 2

o_O

Write a distributed, fault tolerant, replicating, multi datacenter, fast, CAS for

BLOBs.

Reimplementing a lot of things is generally not a

good sign.

Reuse.Don’t reimplement.

HBaseDistributed,

Fault tolerant,Replicating,

Multi datacenter,Fast.

Immutable rows with compact keys, separated into different

column families based on their access patterns.

m: d:

MD5 16 bytes(SHA-1 20 bytes)

Metadata9 bytes

BLOBMany bytes

One table to rule them all.

MAX_FILESIZE => 20G,VERSION => 1,

BLOCKCACHE => true,BLOOMFILTER => ROW

Pre-split into 512 regions at table creation time.

Scala,Finagle,

asynchbase,Varnish

HTTP has a lot to offer.

VerbsGET HEAD PUT DELETE

GET /KwIEec5utYGrKmzXYLgFzg HTTP/1.1Host: b9.sustatic.com

HeadersCache-Control: max-age=<1 year>Last-Modified: <cell timestamp>Content-MD5: <row key: base64>

Content-Disposition: attachment; filename=su.xpi

HBase and HTTP are the perfect tools to build

simple, reliable, fast data services.

Get excited and build things!

Thanks.

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