大文件无变更场景下使用Git LFS的优势咨询（含Packer/CI场景）

Great question—even when your ISO files and installer binaries don’t need updates, Git LFS still brings meaningful benefits to your workflow, especially with your setup involving Packer, submodules, and CI pipelines. Here’s a breakdown tailored to your use case:

1. Keeps Repositories (and Submodules) Lightweight #

Git natively stores every version of every file in your repository history—even if a large file never changes, cloning the repo will still pull that full file size every time. With Git LFS, those big files are replaced with tiny pointer files (usually a few KB) in the Git repo itself, while the actual binary content lives in a separate LFS storage.

For your submodule setup:

• Cloning your main build script repo will only pull the small submodule reference and pointer files, not the entire ISO/installer binaries.
• When you need the actual files (like during a Packer build), you can trigger a targeted LFS pull, saving bandwidth and clone time for both local developers and CI runners.

2. Boosts CI Pipeline Efficiency #

CI environments are often ephemeral, so every second of setup time adds up. Without Git LFS, your CI would have to re-download the full size of your static large files on every run—even if they’ve never changed. With LFS:

• You can configure CI to only pull LFS objects when needed (e.g., right before running Packer), avoiding unnecessary downloads.
• Most CI platforms support caching LFS objects, so subsequent runs can reuse already downloaded binaries instead of re-fetching them, cutting down on pipeline runtime and cloud costs.
• If you ever update the submodule (e.g., to add a new script without touching the ISO), CI only needs to pull the small pointer changes, not re-download the unchanged large files.

3. Maintains a Unified Git Workflow #

Instead of building custom scripts to download ISO/installers from external storage (like wget or curl calls in your Packer config), Git LFS lets you manage these assets using standard Git commands. This means:

• Developers don’t need extra setup steps—just install Git LFS once, and git clone/git submodule update will handle fetching the large files automatically (or on demand).
• Your workflow stays consistent: you track all build dependencies (scripts + binaries) in Git, making it easier to onboard new team members and reduce manual errors from external file downloads.

4. Improves Version Traceability #

Even static files benefit from being tracked in Git LFS. The pointer files in your submodule’s commit history create a clear link between your build scripts (in the main repo) and the exact ISO/installer version used for each build. If you ever need to reproduce a past build, you can check out the specific commit of the submodule, and Git LFS will fetch the exact binary that was used at that time—no guessing which file version was stored in an external drive or cloud bucket.

5. Flexible, Scalable Storage Management #

Git LFS supports multiple storage backends (cloud providers, Git hosting services like GitHub/GitLab LFS, or even local storage). This lets you:

• Separate large binary storage from your code repository, avoiding hitting storage limits on your Git host.
• Apply granular access controls: for example, your CI pipeline can have read-only access to the LFS storage without needing write permissions to the code repo.
• Easily back up or migrate your large files independently of your code history, since they’re stored separately.

内容的提问来源于stack exchange，提问作者N Jones