Backup & Recovery (Rsync/Tar/Dd)

Speed up your rsync transfers by skipping the hash checks

🧩 The Challenge

You ever tried to sync a few terabytes of data over a spotty connection, only to have rsync spend twenty minutes just scanning file sizes and checksums? It drives me crazy waiting for the actual data transfer to start while the disk chugs away in the background.

💡 The Fix

Tell rsync to use size and modification time instead of hashing every single byte. It makes the initial handshake way faster when you are dealing with millions of files.

rsync -av --size-only /source/dir/ /destination/dir/

⚙️ Why It Works

Relying on the modification time and file size allows the daemon to skip the time-consuming process of reading the contents of every file just to check if they match. Most of the time, if the size and timestamp haven’t changed, the data hasn’t either.

🚀 Pro-Tip: Add the -I flag if you get paranoid and actually want to force those checksums later for a final verification run.

Linux Tips & Tricks | © ngelinux.com | 10/31/2026