- High Scalability

The Google Operating System blog has an interesting post on Google's scale based on an updated version of Google's paper about MapReduce.

The input data for some of the MapReduce jobs run in September 2007 was 403,152 TB (terabytes), the average number of machines allocated for a MapReduce job was 394, while the average completion time was 6 minutes and a half. The paper mentions that Google's indexing system processes more than 20 TB of raw data.

Niall Kennedy calculates that the average MapReduce job runs across a $1 million hardware infrastructure, assuming that Google still uses the same cluster configurations from 2004: two 2 GHz Intel Xeon processors with Hyper-Threading enabled, 4 GB of memory, two 160 GB IDE hard drives and a gigabit Ethernet link.

Greg Linden notices that Google's infrastructure is an important competitive advantage. "Anyone at Google can process terabytes of data. And they can get their results back in about 10 minutes, so they can iterate on it and try something else if they didn't get what they wanted the first time."

It is interesting to compare this to Amazon EC2:

$0.40 Large Instance price per hour x 400 instances x 10 minutes = $26.7

1 TB data transfer in at $0.10 per GB = $100

For a hundred bucks you could also process a TB of data!