google

cdc-file-transfer

C++2023–2026

google / cdc-file-transfer · Archived

cdc-file-transfer

Tools for synching and streaming files from Windows to Linux

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13Distinct people

15Mentions

1Explicit recommenders

3.4KGitHub stars

REPOSITORY AT A GLANCE

What to know before exploring

What it is

Tools for synching and streaming files from Windows to Linux

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

Rsync is one of my favorite programs. I use it daily. The CLI is a bit quirky (e.g. trailing slashes), but once you get used to it, it makes sense. And I really always use the…

imiric used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.

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Also in these discussions

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year15 dated mentions

Observed mentions: 2023-01-06 15:41:01 UTC to 2026-03-06 22:50:30 UTC.

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges

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Period	Start (UTC)	End (exclusive, UTC)	Mentions	Submissions	Comments
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	8	2	6
2024	2024-01-01 00:00:00 UTC	2025-01-01 00:00:00 UTC	0	0	0
2025	2025-01-01 00:00:00 UTC	2026-01-01 00:00:00 UTC	4	1	3
2026 (partial)	2026-01-01 00:00:00 UTC	2027-01-01 00:00:00 UTC	3	0	3

What Hacker News says

15 sources

ilyagr·Mar 6, 2026

This is less of a usable tool and more of a concept right now, but there are algorithmic ways to do better than rsync (for incremental transfers, ymmv). https://github.com/google/cdc-file-transfer Hint: I really like the animated gifs on that page but they are best viewed frame-by-frame like a presentation.

In Parsync, a tool for parallel SSH transfers – 7x faster than rsync

vadiml·Jan 27, 2026

I've been working on extending CDC File Transfer to support Linux→Linux and macOS builds. This is an open-source project born from Google Stadia – fast file sync tools (cdc_rsync) and a streaming filesystem (cdc_stream) that use Content Defined Chunking (FastCDC) to transfer only the changed portions of files. Originally Windows→Linux only, designed for game developers to iterate on 40+ GB builds. The CDC-based diffing is up to 30x faster than rsync (1500 MB/s vs 50 MB/s). What I added (40 commits): Linux Client Support: Ported cdc_rsync client to run on Linux (was Windows-only) Added process_linux.cc (~700 lines): Process management using fork/execve Added port_manager_linux.cc: Port detection using POSIX shared memory Now you can sync Linux→Linux, not just Windows→Linux macOS Support: Full build support for macOS (ARM64 and x86_64) Fixe

Read the rest

d 17+ platform-specific issues: /tmp, /var, /etc are symlinks to /private/* – breaks path comparisons POSIX shared memory rounds ftruncate() up to 16KB, rejects shrinking BSD fts_* API reports Bazel runfiles symlinks as FTS_SL not FTS_F strerror(0) returns different strings per platform stat64 doesn't exist on macOS (just use stat) All 41 tests now pass on macOS Infrastructure: GitHub Actions CI for Linux and macOS (self-hosted runner for macOS) Added comprehensive CLAUDE.md for AI-assisted development The project uses Bazel with gRPC, protobuf, and FUSE. Dependencies via git submodules or http_archive. GitHub (original): https://github.com/google/cdc-file-transfer My fork: https://github.com/Vadiml1024/cdc-file-transfer I've been using Claude Code (Anthropic's AI coding assistant) for most of this work. Happy to discuss the experience or the technical challenges.

In CDC File Xfer Google Stadia's rsync replacement now works on Linux and macOS

imiric·Jan 3, 2026Recommendation phrase

Rsync is one of my favorite programs. I use it daily. The CLI is a bit quirky (e.g. trailing slashes), but once you get used to it, it makes sense. And I really always use the same flags: `-avmLP`, with `-n` for dry runs. One alternative I'd like to try is Google's abandoned CDC[1], which claims to be up to 30x faster than rsync in certain scenarios. Does anyone know if there is a maintained fork with full Linux support? [1]: https://github.com/google/cdc-file-transfer

In The rsync algorithm (1996) [pdf]

guest567·Oct 3, 2025

https://github.com/google/cdc-file-transfer the google repo has been archived, Did they give it up?

In CDC File Transfer

rincebrain·Oct 1, 2025

You can find some thoughts on it not working for Linux to Linux, and more broad compatibility, here[1] and here[2]. [1] - https://github.com/google/cdc-file-transfer/issues/56#issuec... [2] - https://github.com/librsync/librsync/issues/242

In CDC File Transfer

kxrm·Oct 1, 2025

No: https://github.com/google/cdc-file-transfer?tab=readme-ov-fi...

In CDC File Transfer

GalaxySnail·Oct 1, 2025Submission

CDC File Transfer

389 points · Open discussion

ljusten·Jan 9, 2023

The same question was asked here: https://github.com/google/cdc-file-transfer/issues/56

In CDC File Transfer

ljusten·Jan 9, 2023

Windows to Windows is being worked on, see https://github.com/google/cdc-file-transfer/compare/main...s.... Linux to Linux is also an option if there is demand, but currently it's Windows to Linux only.

In CDC File Transfer

aembleton·Jan 9, 2023

We also ran the experiment with the native Linux rsync, i.e syncing Linux to Linux, to rule out issues with Cygwin. Linux rsync performed on average 35% worse than Cygwin rsync, which can be attributed to CPU differences. Source: https://github.com/google/cdc-file-transfer

In CDC File Transfer

ljusten·Jan 9, 2023

This is currently being worked on, see https://github.com/google/cdc-file-transfer/compare/main...s...

In CDC File Transfer

c7b·Jan 9, 2023

Slightly OT, but I like the schematic gifs used in the Readme.md (pretty amazing doc overall!) like this one [0]. Does anyone have suggestions what tools they might have used (or might be used in general) to create those? [0] https://github.com/google/cdc-file-transfer/blob/main/docs/l...

In CDC File Transfer

zmmmmm·Jan 9, 2023

The documentation in the code itself is pretty great as well: https://github.com/google/cdc-file-transfer/blob/main/fastcd...

In CDC File Transfer

cglong·Jan 8, 2023Submission

CDC File Transfer

917 points · Open discussion

Poudlardo·Jan 6, 2023Submission

Google open sourced CDC File Transfer from the ashes of Stadia

4 points · Open discussion