v8.5.5 scheduler: network slow store scheduler enhancement (#22269)

[ti-chi-bot]

This is an automated cherry-pick of #22269

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What is changed, added or deleted? (Required)

Which TiDB version(s) do your changes apply to? (Required)

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For details, see tips for choosing the affected versions (in Chinese).

• master (the latest development version)
• v9.0 (TiDB 9.0 versions)
• v8.5 (TiDB 8.5 versions)
• v8.1 (TiDB 8.1 versions)
• v7.5 (TiDB 7.5 versions)
• v7.1 (TiDB 7.1 versions)
• v6.5 (TiDB 6.5 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)

What is the related PR or file link(s)?

• This PR is translated from: scheduler: network slow store scheduler enhancement docs-cn#21196
• Other reference link(s): ref Enhance Slow Store Scheduler tikv/pd#9359

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[gemini-code-assist]

Summary of Changes

Hello @ti-chi-bot, 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 significantly enhances the TiDB scheduler's resilience by extending its evict-slow-store-scheduler to identify and manage TiKV nodes suffering from network performance issues, in addition to existing slow-disk detection. This new capability, available in recent TiDB versions, allows for proactive leader eviction from network-impaired nodes, thereby improving overall cluster stability and performance by reducing the impact of network jitter on data operations. The changes include new configuration options for TiKV and comprehensive documentation updates to guide users on enabling and utilizing this feature.

Highlights

• Slow-Network Node Detection: Introduced a new mechanism in TiKV (v8.5.5 and v9.0.0) to detect nodes experiencing network slowness by probing network latency and calculating a NetworkSlowScore.
• Enhanced evict-slow-store-scheduler: The evict-slow-store-scheduler in PD is now capable of handling both slow-disk and slow-network nodes, automatically evicting Region leaders from identified slow nodes to mitigate performance impact.
• New TiKV Configuration: Added a new TiKV configuration parameter, raftstore.inspect-network-interval, to control the frequency of network detection for slow-network node identification.
• Documentation Updates: Updated best practices and pd-control documentation to reflect the new slow-network node detection feature, including how to enable and configure it, and how to manage the recovery-duration for slow nodes.

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[gemini-code-assist]

Code Review

This pull request enhances the documentation for the scheduler to include the new network slow store detection feature. The changes are well-structured and add valuable information to pd-scheduling-best-practices.md, pd-control.md, and tikv-configuration-file.md. My feedback includes a few minor suggestions to improve clarity and adhere to the documentation style guide.

[ti-chi-bot]

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[ti-chi-bot]

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