Fast_copy new release with new features

v2.1.0 Feature

This release adds 3 notable features for engineering teams evaluating rollout.

Published 4mo Backup & Recovery

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✓ No known CVEs patched

Read the diff → Tool health → What is this tool? →

✓ No known CVEs patched in this version

Topics

backup cli copy-tool cross-platform deduplication file-copy

+14 more

file-transfer linux macos nas python remote-copy rsync-alternative scp-alternative ssh ssh-transfer synology tar-streaming usb-copy windows

Affected surfaces

crypto_tls

Summary

AI summary

Updates Cross-Run Dedup Database, NTFS Symlink Fix, and Stronger Hash Algorithm across a mixed release.

Full changelog

What's New

Stronger Hash Algorithm

xxh64 → xxh128 (128-bit) — collision probability reduced from ~1 in 2³² to ~1 in 2⁶⁴
Fallback upgraded from MD5 to SHA-256

Cross-Run Dedup Database

Persistent SQLite hash cache at the drive root (.fast_copy_dedup.db)
Shared across all destination folders on the same drive
Copying the same source to test8/ then test9/ → zero bytes copied on the second run, all files hard-linked

Reports which existing folders matched:

Cross-run dups:  3696 files (324.9 MB) — already on drive, will link instead of copy
  → test8/: 3696 files matched

Source hash caching — subsequent runs skip re-hashing (100% cache hits)
--no-cache flag to disable

Faster Verification

Single os.walk() pass replaces thousands of individual stat() calls on USB

NTFS Symlink Fix

Broken symlinks on NTFS (via Linux) now fall back to real copies automatically

Performance Example

| Run | Destination | Data Written | Time |
|-----|-------------|-------------|------|
| 1st | test8/ | 302.4 MB | 5.2s |
| 2nd | test9/ | 0 B (all linked) | 1.6s |

SHA-256 Checksums

d2dad98eab06e93c09da1bcf0d9a2c70a321d8d90e9ec419e335d4388fed274b  fast_copy.py
28c60abb1819e3beeed34120f11aa78e496aacf4b780e91420cd6abee01dc56b  build.py

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