Google Strategy: Tree Distribution of Requests and Responses
Tuesday, February 1, 2011 at 7:30AM
Todd Hoff in Strategy, google

If a large number of leaf node machines send requests to a central root node then that root node can become overwhelmed:

One solution to this problem is a strategy given by Dr. Jeff Dean, Head of Google's School of Infrastructure Wizardry, in this Stanford video presentation: Tree Distribution of Requests and Responses.

Instead of having a root node connected to leaves in a flat topology, the idea is to create a tree of nodes. So a root node talks to a number of parent nodes and the parent nodes talk to a number of leaf nodes. Requests are pushed down the tree through the parents and only hit a subset of the leaf nodes.

With this solution:

In Google's search system, for example:

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