Cosmos DB Optimization

John Savill's Technical Training walks through practical ways to optimize Azure Cosmos DB cost and performance, focusing on throughput (RUs), service tiers, partitioning, and data model/design choices.

Cosmos DB Optimization

This session covers how to optimize Azure Cosmos DB deployments with a focus on cost/performance trade-offs. Topics include throughput models (Request Units), service options, and how data model and partitioning decisions directly affect RU consumption.

Chapters covered (video outline)

• Introduction
• Service options and structure
• Request Units (RUs)
• Free SKU
• Provisioned throughput
  • Manual
  • Autoscale
• Configuration
• Account throughput limit
• Partitions
• What should I use?
• Optimizing design
  • Optimizing RU usage
  • Importance of the partition key
  • High cardinality
  • Document size
  • Global secondary index
  • Storage-heavy vs write-heavy patterns
• Summary

Key optimization themes called out

Throughput and pricing model choices

• Understanding and managing Request Units (RUs)
• Choosing between:
  • Free SKU
  • Provisioned throughput
    • Manual provisioning
    • Autoscale provisioning
• Reviewing pricing-related options such as reservations

Partitioning and data model design

• How partitions impact scalability and performance
• Why the partition key is a critical design decision
• Using high-cardinality partition keys to avoid hot partitions
• Considering document size and its impact on throughput and storage
• Index considerations (including mention of a global secondary index)
• Thinking in terms of workload shape:
  • Storage-heavy
  • Write-heavy

Links and resources

• Whiteboard diagram: https://github.com/johnthebrit/RandomStuff/raw/master/Whiteboards/CosmosDBOptimization.png
• Cosmos DB Request Units: https://learn.microsoft.com/azure/cosmos-db/request-units
• Cosmos DB Pricing: https://azure.microsoft.com/pricing/details/cosmos-db/standard-provisioned/
• Cosmos DB Reservations: https://learn.microsoft.com/azure/cosmos-db/reserved-capacity

Additional learning resources from the author

• Recommended Learning Path for Azure: https://learn.onboardtoazure.com
• Certification Content Repository: https://github.com/johnthebrit/CertificationMaterials
• Weekly Azure Update playlist: https://youtube.com/playlist?list=PLlVtbbG169nEv7jSfOVmQGRp9wAoAM0Ks
• Azure Master Class playlist: https://youtube.com/playlist?list=PLlVtbbG169nG169nGccbp8VSpAozu3w9xSQJoY
• DevOps Master Class playlist: https://youtube.com/playlist?list=PLlVtbbG169nFr8RzQ4GIxUEznpNR53ERq
• PowerShell Master Class playlist: https://youtube.com/playlist?list=PLlVtbbG169nFq_hR7FcMYg32xsSAObuq8
• Certification Cram playlist: https://youtube.com/playlist?list=PLlVtbbG169nHz2qfLvPsAz9CnnXofhmcA
• Mentoring content playlist: https://youtube.com/playlist?list=PLlVtbbG169nGHxNkSWB0PjzZHwZ0BkXZZ
• FAQ: https://savilltech.com/faq

Notes

• The video description notes subtitles can be enabled and auto-translated, with a demo: https://youtu.be/v5b53-PgEmI