just a sanity check please?
The documentation site states
Compress all packets, including file data. This is recommended if the folders contents are mainly compressible data such as documents or text files.
I have a usage case where 7zip manages to compress files from 3400MiB down to 306MiB.
This is using command line args :
7z.exe a -bt -mx=5 -mmt
-mx5 means compression lvl 5 for 7z archive type (LZMA:24)
Given the above, would it be a good idea to set syncthing to compress always ?
What kind of compression ratio would be the result?
How could I test this to see some numbers with & without compression ?
I don’t think you can reasonably compare this. We compress individual small packets where as you compress a single large blob. Obviously there will be much more overlap over a single large blob than thousands of small packets.
You can split your uncompressed archive into N 128kb sized files, and then compress each file individually using lz4 and see what the grand total in size ends up being for all N compressed files…
You can set it up, sync the folder from the beginning. Change the compression settings, remove the files and the index database on the receiving side and transfer it again. Compare the transferred data amounts in the GUI.
Or just enable it and don’t worry about it. I’ll save you some bytes, and cost almost nothing in CPU time (on modern-ish hardware).