Skip to content

Mount ReFS Dev Drive on Windows to speed up small-file I/O #5065

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
pietern wants to merge 8 commits into
base: main
Choose a base branch
from
Draft

Mount ReFS Dev Drive on Windows to speed up small-file I/O #5065

Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
c3b164d
ci: mount ReFS Dev Drive on Windows to speed up small-file I/O
pietern Apr 22, 2026
11c5c44
Drop TEMP/TMP redirect from Dev Drive step
pietern Apr 22, 2026
931c8a9
Junction the workspace onto the Dev Drive on Windows
pietern Apr 22, 2026
59d49a7
Revert "Junction the workspace onto the Dev Drive on Windows"
pietern Apr 22, 2026
9908fe7
Redirect TEMP + Go caches via C:\a\_fast junction
pietern Apr 22, 2026
fce8d2d
Use directory symlink instead of junction for Dev Drive
pietern Apr 22, 2026
8685de3
Revert "Use directory symlink instead of junction for Dev Drive"
pietern Apr 22, 2026
f5621c6
Revert "Redirect TEMP + Go caches via C:\a\_fast junction"
pietern Apr 22, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 33 additions & 0 deletions .github/actions/setup-build-environment/action.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,39 @@ inputs:
runs:
using: 'composite'
steps:
# Mount a ReFS Dev Drive on Windows and route Go's cache dirs onto it.
# The default C: drive on GH runners is ~4.3k IOPS; a Dev Drive is ~127k.
# Go build compilation is small-file-heavy and benefits most. The
# `-DevDrive` flag is Win11 22621+ / WS2025; older hosts fall back to plain
# ReFS which is still markedly faster than C:. Must run before setup-go so
# GOCACHE/GOMODCACHE save/restore lands on the drive.
#
# Note: TEMP/TMP are intentionally NOT redirected. Doing so puts
# `t.TempDir()` on Z: while the checkout and uv's Python package cache stay
# on C:, which triggers `ValueError: Paths don't have the same drive` in
# older databricks-bundles versions under `bundle/python/*` tests
# (`os.path.commonpath` can't span drives).
- name: Mount ReFS Dev Drive (Windows)
if: runner.os == 'Windows'
shell: pwsh
run: |
$vhdPath = "$env:RUNNER_TEMP\devdrive.vhdx"
New-VHD -Path $vhdPath -SizeBytes 20GB -Dynamic | Out-Null
$disk = Mount-VHD -Path $vhdPath -Passthru |
Initialize-Disk -PartitionStyle GPT -Passthru
New-Partition -DiskNumber $disk.Number -UseMaximumSize -DriveLetter Z | Out-Null
try {
Format-Volume -DriveLetter Z -FileSystem ReFS -DevDrive `
-NewFileSystemLabel DevDrive -Confirm:$false -Force | Out-Null
} catch {
Format-Volume -DriveLetter Z -FileSystem ReFS `
-NewFileSystemLabel DevDrive -Confirm:$false -Force | Out-Null
}
New-Item -ItemType Directory -Path Z:\go-build,Z:\go-mod,Z:\go-tmp | Out-Null
"GOCACHE=Z:\go-build" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV
"GOMODCACHE=Z:\go-mod" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV
"GOTMPDIR=Z:\go-tmp" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV

- name: Checkout repository and submodules
uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

Expand Down
Loading