PMM-15091: stop double-counting RAID md devices in Disk Details

[mattiasimonato]

Ticket number: PMM-15091

Feature build: SUBMODULES-4488

Total Performance on Disk Details sums metrics over $device. That variable already skipped LVM devices (dm-*), but still included both the RAID array (md0) and its member disks (sda, sdb). Summing those together counted the same I/O twice, so panels showed about 2× real IOPS/throughput.

Fix: exclude RAID arrays in the $device query with device!~"dm-.+|md.+", same idea as LVM. Panels keep using $device, so Total Performance stops double-counting. Used md.+ (not md[0-9].+) so names like md0 match.

Summary by CodeRabbit

• Bug Fixes
  • Updated the Device filter in the Disk Details dashboard to properly exclude both device-mapper and software RAID devices from monitoring queries, improving data accuracy.

[Copilot]

Pull request overview

Updates the Disk Details Grafana dashboard variable query to avoid double-counting I/O when both Linux software RAID (md*) devices and their member disks are present, improving the accuracy of “Total Performance” panels that aggregate over $device.

Changes:

• Exclude md* devices from the $device template variable query (in addition to existing dm-* exclusion) to prevent RAID array + member disk double aggregation.
• Apply the same exclusion to both the variable definition and query fields for consistency.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 37.03%. Comparing base (31318c7) to head (a4afc89).
⚠️ Report is 87 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5675      +/-   ##
==========================================
- Coverage   43.59%   37.03%   -6.56%     
==========================================
  Files         415      215     -200     
  Lines       43134     7168   -35966     
  Branches        0      592     +592     
==========================================
- Hits        18804     2655   -16149     
+ Misses      22454     4317   -18137     
+ Partials     1876      196    -1680     

Flag	Coverage Δ
admin	34.96% <ø> (+0.17%)	⬆️
agent	?
managed	?
unittests	41.29% <ø> (?)
vmproxy	?

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: b50241e7-0225-47db-9dc7-8aab900968f0

📥 Commits

Reviewing files that changed from the base of the PR and between c6029fc and a4afc89.

📒 Files selected for processing (1)

• dashboards/dashboards/OS/Disk_Details.json

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Walkthrough

The OS Disk Details dashboard now excludes both device-mapper (dm-*) and software RAID (md*) devices from the Device variable query.

Changes

Disk device filtering

Layer / File(s)	Summary
Update Device variable query dashboards/dashboards/OS/Disk_Details.json	The Device variable definition and nested query now exclude dm-* and md* device names.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Suggested reviewers: nailya

Poem

A rabbit checks the disks with care,
And skips mapped devices there.
dm-* and md* hide from view,
The dashboard query now filters true.
Hop, hop—clean results come through!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: excluding RAID md devices from the Disk Details device variable to prevent double-counting in the Total Performance metric.
Description check	✅ Passed	The description includes the ticket number and feature build, explains the problem and solution clearly, and provides implementation details. The API documentation checkbox is not applicable here.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch PMM-15091-exclude-md-from-disk-details

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