Mastering rsync: Compile and Sync Files on Embedded Boards Efficiently

What is rsync?

rsync (remote sync)

is a file synchronization tool that can sync between local directories or between local and remote devices.

Unlike scp, rsync checks existing files on both sides and transfers only changed parts (by size or modification time).

Using rsync

Demonstration using a PC and a development board. Both sides must have rsync installed.

Note: Both the sender and receiver must have rsync installed.

The board lacks rsync, so we compile it from source.

Download rsync source from https://download.samba.org/pub/rsync/.

Extract, enter directory, create a temporary folder:

tar -xvf rsync-3.2.3.tar.gz
cd rsync-3.2.3/
mkdir tmp

Generate a cross‑compilation Makefile:

./configure --prefix=$PWD/tmp --host=arm-linux-gnueabihf CC=arm-linux-gnueabihf-gcc

If errors occur, disable SIMD as shown by ./configure --help and add --disable-simd (or other disables) to the configure command.

./configure --prefix=$PWD/tmp --disable-simd --host=arm-linux-gnueabihf CC=arm-linux-gnueabihf-gcc

Further errors may require disabling additional features:

./configure --prefix=$PWD/tmp --disable-simd --disable-openssl --disable-xxhash --disable-zstd --disable-lz4 --host=arm-linux-gnueabihf CC=arm-linux-gnueabihf-gcc

When configuration succeeds, a Makefile is generated.

Note: If more errors appear, adjust the configure options accordingly.

Compile and install:

make
make install

The compiled rsync binary appears in the tmp folder; copy it to the board’s /usr/bin:

scp rsync [email protected]:/usr/bin

Demonstration of rsync usage:

Create 100 files on the board, then sync to PC:

rsync -avzu --progress [email protected]:/root/test .

-a: archive mode, preserves metadata. -v: verbose output. -z: compress data during transfer. -u: skip files that are newer on the receiver. --progress: show progress.

After creating another 100 files on the board, running the same command continues syncing only the new files.

This concludes the brief guide to using rsync for efficient file synchronization on embedded devices.