Best practices for backing up small mailserver to remote location

[Kenneth Porter]

On 8/7/2018 5:08 PM, Adi Pircalabu wrote:
> - Since you're on dynamic IP at home, set up a VPN tunnel using the 
> mailserver as server and HTPC as client. OpenVPN is ubiquitous and 
> widely supported.
> - rsync your mailboxes using the tunnel connection.
> This way you can back up your entire server, not only the mailboxes.

Instead of openvpn, I use openssh. Use compression in the ssh tunnel, 
not the rsync connection, as rsync compression tends to be buggy and 
interrupts the download. I run sshd on a non-standard port to keep my 
logs relatively free of script kiddy noise from people looking for an 
ssh connection to crack. Run fail2ban to lock out the remaining script 
kiddies. Use a client certificate to log in with ssh unprompted, making 
it easy to download in a cron job.

Here's an example of scripting the download. Uncomment the DRYRUN line 
for testing, then comment for production. Add more rsync commands to 
back up different partitions. The --one-file-system prevents rsync from 
trying to back up /dev, /proc, and /sys. The --delete option will remove 
local files that were deleted on the remote server. Use that set of 
options once you're happy that the backup is working right.

#!/bin/sh
#set -e
set -x
#DRYRUN=--dry-run
#RSYNC_OPTIONS="$DRYRUN --one-file-system -avH --delete"
RSYNC_OPTIONS="$DRYRUN --one-file-system -avH"
DEST=/home/rsync/Server1

# Allow one hour so we don't burn up our bandwidth allowance
# from a command error

time timeout 1h \
rsync -e 'ssh -C -p 1234' $RSYNC_OPTIONS example.com:/ ${DEST}/ \
         --exclude tmp

# add more rsync commands here for other partitions