what is the best practice to archive groupwise mailboxes

"best practice" depends on the industry and company and whether any regulatory requirements need to be met.

Anything having to do with health insurance or medical care would fall under HIPPA, for one example.  Large public corporations fall under Sarbanes-Oxley, for another.  

If you don't have any regulatory requirements for email retention, unless you need to keep them for legal purposes, it may actually be advisable to permanently delete them, as a matter of policy - believe it or not - for legal purposes.  It depends on the situation.  If you have a documented policy that all emails will be deleted after x months untouched for example, or all emails will be deleted unless they're manually archived, then it's actually been found to be a "cover" of sorts, legally.  However, if your policy is to retain all of your emails, then that tactic would not be recommended ;).  If the "law" part of your member ID means you work for a law firm, perhaps you could get some "free" legal advice to help you decide.

You may want to look into email management software, which is intended to facilitate regulatory compliance for retention and retrieval.

yes i work for a law firm, and we would like to keep our data for later purposes, that for sure. with your expertise, can you or would you back up to a dvd or other media for later uses? and if so, how is it done, and is it difficult to retrieve.

Retreival of deleted account mailbox data is kind-of problematic, in that mailbox data, whether in the PO database or in an archive, depends on the user ID identifier, also known as the FID.  If the mailbox's or archive's FID doesn't match up with the user ID's FID, you won't be able to attach the archive or mailbox.

This procedure for recovering a deleted user is for 6.5 but should apply to 7, to the best of my knowledge: http://support.novell.com/docs/Tids/Solutions/10082831.html

That document refers to another TID for how to set up a restore area and perform a mailbox backup/restore (sort-of like the infamous "brick-level" of Exchange): http://support.novell.com/cgi-bin/search/searchtid.cgi?/10076955.htm

That document links to the GroupWise 6 documentation on backup/restore of GroupWise databases.  Documentation for GW7 for backup/restore of databases also exists, so I suggest you read that: http://www.novell.com/documentation/gw7/gw7_admin/index.html?page=/documentation/gw7/gw7_admin/data/a8n802e.html

The files produced in a backup could be burned to CD or DVD for archival storage, just as easily as being put on tape.  Are you using a third-party backup package like ARCserve or BE, that can use the ENABLEGW switch on the TSAFS? (assuming you're on reasonably-current NetWare/OES...)

I suggest that you might want to consider using a backup software package that can do individual user and mailbox backups and restores, and can mount removable media like DVD+/-RW for the backup media.  That way, you could set up an archive for to-be-deleted mailboxes and delete them after the archive is done.  I suggest you test your procedure on a "dummy" user first, and document the steps.

this might sound stupid, but couldnt i archive what i need to backup, then burn the specific folder than later down the road if i need it, i can just place back where it originally was?