Google and LargeScientific Datasets

or

How To Move 100TB

Jon Trowbridge

Google

Space Telescope Science Institute

March 15, 2007

Organize the world’s information and make it universally accessible

and useful.

Motivating Problem

What if a piece of information is too large to efficiently transmit across

the Internet as it exists today?

“Never underestimate the bandwidth of a station wagon full of tapes hurtling down the

highway.”- Andrew Tanenbaum (?)

Large Dataset Archive

• Move data by shipping hard drives

• Centralized repository stored on Google’s infrastructure

• Accepting data from all disciplines, but it must be open and free

• Ulimate goal: Promiscuous distribution

Nice Properties ofPhysical HD Shipment

• Uses commodity technologies: Linux, SATA, ext2

• High throughput

• Trivially scalable

• Cheap and easy: $2400 for 3T

• Rapidly getting cheaper

Real-World Throughputs

Method MiB/s GiB/hr TB/day hrs/TB1200 baud modem 1.14E-04 4.02E-04 9.43E-06 2545166My Home DSL (downstream) 0.3 1.41 0.03 728.18Ethernet: 10baseT 0.8 2.81 0.07 364.09Ethernet: 100baseT 8 28.13 0.66 36.41End-to-end physical shipment 0.88 27.42HD Transfer 30 105.47 2.47 9.71FedEx phase of shipment 3.00 8.00Ethernet: Gigabit 60 210.94 4.94 4.85LBNL, 2002: 10.6 GiB/s 10854 38160 894.38 0.03

The Cost of 1GB of Storage

• 1986: $100,000

• 1990: $10,000

• 1994: $1,000

• 1997: $100

• 2000: $10

• 2004: $1

• Today: About 40¢

Creative Computing - February, 1980

Not-So-Nice Properties ofPhysical HD Shipment

• Physical objects break, get stolen, occasionally explode

• HD copying bottleneck

• Customs/duties make international shipments more complicated

The Big Question

What happens when every astronomer has the complete Hubble Legacy Archive on the

computer in their office?

The Big Question

What happens when every high-school student has the complete

Hubble Legacy Archive on thecomputer in their bedroom?