i use rsync to transfer my backups around. to better utilize available bandwidth i run multiple rsyncs in parallel… but from time to time i’ve noticed failures that on the client side.
i was getting:
rsync: connection unexpectedly closed (0 bytes received so far) [sender] rsync error: unexplained error (code 255) at io.c(601) [sender=3.0.7] ssh_exchange_identification: Connection closed by remote host rsync: connection unexpectedly closed (0 bytes received so far) [sender] rsync error: error in rsync protocol data stream (code 12) at io.c(601) [sender=3.0.7] rsync: connection unexpectedly closed (0 bytes received so far) [sender]ssh_exchange_identification: Connection closed by remote host
after some investigation it turned out that rsyncs run one after another don’t fail… i started digging around and found that setting MaxStartups to 100 in /etc/ssh/sshd_config on the receiving server solves the problem.