faster rsync (ssh cipher choice)

Perhaps the bottleneck isn’t always bandwidth – but does changing ssh cipher make any difference?

Using a derivative of :

rsync -W --delete --no-owner --no-group --no-perms \
    -e ssh \
    -arv /source/ remote@destination:/destination/path/

In unscientific tests, it looks like ssh parameters might do something when copying a 4GiB file between two random virtual machines in different data centres, but both in London.

SSH VariantSpeed
-e “ssh”~45MB/s
-e “ssh -x -T”~44MB/s
-e “ssh -x -T -c”~42MB/s
-e “ssh -x -T -c aes128-ctr”~47MB/s
-e “ssh -x -T -c”~50MB/s
-e “ssh -x -T -c “~45MB/s

I’m not sure if these results are particularly insightful / useful.



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2 responses to “faster rsync (ssh cipher choice)”

  1. Duncan Avatar

    You can rebuild ssh and sshd with a null cypher for benchmark purposes if you’re interested. Turning compression on and off can also make a big difference depending on the CPU availability on both ends. There are also multi-threaded versions of both client and server that can help.

  2. David Goodwin Avatar

    Thanks – I was sure I’d written something before about speed(s) but couldn’t immediately find it 🙂 this was a poor mans attempt at stopping myself from doing pointless premature optimisations in the future !

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