UNIX for Dummies Questions & Answers

We're using Deltacopy's distribution of Cygwin Rsync (v3.0.4, I believe) to backup two large Virtualbox virtual hard drives from our work Windows 7 VM host, over the internet through Logmein Hamachi VPN, to an XP PC in my boss's basement. I have rsync running in a batch file which monitors the return error code rsync gives, and restarts the rsync command if the error code isn't 0. It works just fine. Mostly...

Occasionally the connection goes down for a few seconds up to a few minutes (I've troubleshooted the loss of the connection to my boss's home ISP disconnecting; the work internet connection is fine). Rsync will throw an error 12, then continue throwing error 10's every time the batch file tries to restart the backup, until the connection re-establishes itself, usually within three minutes, sometimes right away.

I have been looking for a way to get the rsync process to not fail but wait patiently for the connection to come back.

Here's my command:

rsync.exe -v -rlt -z -h --chmod=a=rw,Da+x --delete --progress "/cygdrive/E/VMbackups/Server2003.vdi" "ham.achi.ip.address::BU1/VMbackups/Server2003.vdi"

I found the "--timeout" switch which sets a timeout limit on I/O, but defaults to no timeout if not used. (I think...)

There's also "--contimeout", which sets a limit on how long rsync will wait to establish a connection. (Does this apply for waiting for a connection to re-establish?)

Is there anything to make rsync wait a while for a previously active but presently dropped connection to reconnect before throwing an error?

I did try --timeout=600 and --contimeout=600, but neither enabled the rsync to wait through a 10-second dropout of the network connection.