addition to the documentation

[J]

Hey, 

wanted to add the following small explanation to the backup section:

ZFS

optional: create a mountpoint for your mails
-> sudo zfs create path/to/Mail
allow your user to create snapshots
-> sudo allow -u USERNAME snapshot path/to/Mail
add a wrapper like this around your offlineimap [not sure if this could
be called from within offlineimap]
#########
#!/usr/bin/env bash
zfs snapshot path/to/Mail@$(date +%Y%m%d%H%M%S)offlineimap
/path/to/offlineimap -c 
#########

that way will work for creating filesystem snapshots and prevent
offlineimap to do massive data destruction

Greets
Tester J
                                                     
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