cloud: update node_storage_used_bytes metric description

[huoyao1125]

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[ti-chi-bot]

Hi @huoyao1125. Thanks for your PR.

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[gemini-code-assist]

Summary of Changes

Hello @huoyao1125, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request improves the documentation for Prometheus and Grafana integration by clarifying the meaning of a specific storage metric. The update ensures that users have a more accurate understanding of what the tidbcloud_node_storage_used_bytes metric represents and provides guidance on how to correctly derive disk usage rates, thereby enhancing the reliability of monitoring insights.

Highlights

• Documentation Clarification: The description for the tidbcloud_node_storage_used_bytes Prometheus metric has been updated to provide a more precise definition.
• Disk Usage Calculation Guidance: New instructions were added to explain how to accurately calculate the disk usage rate for TiKV/TiFlash nodes using available capacity metrics.

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Changelog

• tidb-cloud/monitor-prometheus-and-grafana-integration.md
  • Updated the description for the tidbcloud_node_storage_used_bytes metric to include details on what it reflects (logical data size, excluding overhead) and how to calculate accurate disk usage rate.

Activity

• Initial pull request created by huoyao1125.

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[gemini-code-assist]

Code Review

This pull request improves the clarity and completeness of the tidbcloud_node_storage_used_bytes metric description. The added explanation provides valuable context on how this metric is calculated and offers a formula for users to determine the accurate disk usage rate, which enhances the overall understanding for users.

[JaySon-Huang]

lgtm

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[hfxsd]

/ok-to-test

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-02-26 06:27:43.257359767 +0000 UTC m=+336335.772154376: ☑️ agreed by overvenus.
• 2026-02-26 06:32:59.224160852 +0000 UTC m=+336651.738955461: ☑️ agreed by hfxsd.

[hfxsd]

/approve

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