FEATURE: Deduplicate S3 uploads in backups using hardlinks#37261
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When generating backups with S3 uploads, identical files (same original_sha1) are now downloaded once and hardlinked for duplicate paths instead of downloading each file separately. This addresses the backup size explosion caused by secure uploads duplicating files across different security contexts. For example, a site with 432GB of uploads but only 26GB of unique content will now generate a ~26GB backup instead of ~432GB. How it works: - Group uploads by original_sha1 (the real content hash) - Download only the first file for each unique hash - Create hardlinks for remaining paths with the same content - tar preserves hardlinks, storing data only once Fallback: If hardlinking fails (cross-filesystem, permissions), the file is downloaded normally to ensure backup completion.
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gschlager
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Jan 22, 2026
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When generating backups with S3 uploads, identical files (same original_sha1) are now downloaded once and hardlinked for duplicate paths instead of downloading each file separately.
This addresses the backup size explosion caused by secure uploads duplicating files across different security contexts. For example, a site with 432GB of uploads but only 26GB of unique content will now generate a ~26GB backup instead of ~432GB.
How it works:
Fallback: If hardlinking fails (cross-filesystem, permissions), the file is downloaded normally to ensure backup completion.