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ADR: Spanner Configuration for Topology Service

Aaron Richterrequested to merge
cells_ts_spanner_multiregion into main

Why is this change being made?

This MR updates the Topology Service design documentation to specify our decision to use the nam11 multi-region configuration for Cloud Spanner. After evaluating several multi-region configurations (including nam8 with Asia/Europe replicas and nam-eur-asia3), we determined that nam11 provides the optimal balance of cost-effectiveness, resilience, and performance for our Topology Service requirements at this time.

The update provides concrete cost estimates, configuration details, and justification for this important architectural decision, improving transparency and aiding future planning. This information is critical for budgeting purposes and ensures stakeholders understand the infrastructure implications of our Cells architecture.

This decision was made by consensus the cells-infrastructure team conversation in this thread on March 27, 2025, where we compared various configurations.

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Commits

  • Spanner Multi-Region nam11
Edited by Aaron Richter

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