Instead of relying on Gmail’s feeble 2-3GB of storage space, Google Tutor shows us how we can backup all the emails through Google Groups.
1) Create a new Google Group. Name it with something like “yourGMailaddress+archive” or “archivefor+yourGmailaddor” something similar.
2) Give it a description that will give you a hint that this is your backup archive for your Gmail.
3) Set Access level to “Restricted” since this would only be your GMail backup and archive.
4) Skip the “Invite members” step.
5) Go to “Group settings”
6) In the “Advanced” tab, click on the “Use Google Groups to manage remote archive” option. Enter your GMail address instead of a non-Google Grooup mailing list.
7) Click “Save Changes”. Remember to copy-paste the e-mail address in step number # 3. You’ll need it later on when we setup your GMail to forward messages to this Google Group.
8) Log on to your GMail account.
9) Go to “Settings.” From here you have two options:
a) Set up your GMail to forward all your incoming messages to your archive Google Group.
a.1) Paste the Google Group archive e-mail we took note of earlier into the forwarding e-mail field.
b) Create a “Filter” to specify which messages to forward to your Google Group archive.
b.1) Paste the Google Group archive e-mail address we took note of earlier into the “Forward it to” field.
Apply an appropriate label if you wish, then click “Create filter”.
Using Google Groups To BackUp Gmail – [GoogleTutor]