Method and apparatus for minimizing storage of common attachment files in an e-mail communications server
View Patent ↗The present invention provides an e-mail communications system that minimizes the number of duplicate copies of common attachment files to e-mail communications that are stored in the mail store of an e-mail server. When the e-mail server receives an e-mail attachment file that is larger than a threshold size, the server performs a database search for another copy of the attachment file in the mail store. If another copy is located, the system creates a pointer in the mail store that associates the located attachment file with the e-mail for the additional recipient(s). Attachment files are deleted only after the recipients of the associated e-mail communications delete each of the respective e-mails.
1. A method of storing attachment files to e-mail communications received in an e-mail server, comprising:
responsive to the e-mail server receiving an e-mail communication containing an attachment file, the e-mail server extracting header information from the e-mail communication and storing the e-mail header information in a mail store;
the e-mail server extracting attachment file header information from the attachment file contained in the e-mail communication;
the e-mail server comparing the extracted attachment file header information with attachment file header information from other attachment files previously stored in the mail store to determine whether the attachment files received with the e-mail communications are duplicates of previously stored files;
if an attachment file is a duplicate, the e-mail server storing a link in the mail store between the e-mail header information and the previously stored attachment file; and
then the e-mail server removing the attachment file from the e-mail communication.
2. The method of storing attachment files to e-mail communications according to claim 1 , further comprising:
if an attachment file is not a duplicate of a previously stored attachment file, then storing the attachment file in the mail store and storing a link in the mail store between the e-mail header information and the attachment file to the received e-mail communication.
3. The method of storing attachment files to e-mail communications according to claim 2 , further comprising:
deleting the e-mail header information stored in the mail store and the link
between the e-mail header information and the corresponding attachment file in response to a delete request; and
deleting the corresponding attachment file if there are no links remaining to the attachment file.
4. The method of storing attachment files to e-mail communications according to claim 1 , wherein e-mail messages in the e-mail communications are stored with the corresponding e-mail header information in the mail store.
5. The method of storing attachment files to e-mail communications according to claim 1 , wherein the header information extracted from the attachment files includes a designation of file type.
6. The method of storing attachment files to e-mail communications according to claim 5 , wherein the step of comparing extracted attachment file header information is performed by searching the previously stored attachment files that are designated as the same file type as the attachment file to the received e-mail communication.
7. The method of storing attachment files to e-mail communications according to claim 5 , wherein the header information extracted from the attachment files further includes at least one of: size, creation date, revision date, author, software type, version, and revision number.
8. The method of storing attachment files to e-mail communications according to claim 1 , wherein the step of comparing extracted attachment file header information is performed only when the size of the attachment file is greater than a predetermined size.
9. An e-mail communications server comprising:
an MTA server for receiving e-mail communications from an external network;
a mail store for storing e-mail communications received by the MTA server;
a POP server for downloading e-mail communications from the mail store to client computers through an internal network; and
e-mail attachment file checking software for determining, responsive to the MTA server receiving an e-mail communication containing an attachment file, whether the attachment file in the received e-mail communication is a duplicate of an attachment file that was attached to previously-received e-mail communications in the mail store,
wherein the mail store removes duplicate attachment files from e-mail communications and creates links from received e-mail communications to the corresponding attachment files in the mail store after the e-mail attachment file checking software determines that the attachment file in the received e-mail communication is a duplicate of an attachment file in the mail store.
10. The e-mail communications server according to claim 9 , wherein the mail store further comprises a database for storing the links from received e-mail communications to the attachment files.
11. The e-mail communications server according to claim 10 , wherein the mail store further comprises a first attachment storage database for storing attachment files that are each associated with a single e-mail communication, and a second attachment storage database for storing attachment files that are each associated with a plurality of e-mail communications.
12. The e-mail communications server according to claim 9 , further comprising e-mail file attachment size checker software for detecting the size of attachment files in received e-mail communications, wherein the e-mail attachment file checking software only checks attachment files that are greater than a predetermined size.
13. The e-mail communications server according to claim 9 , wherein the e-mail attachment file checking software extracts properties associated with the attachment files in the received e-mail communications, and searches the mail store for attachment files having the same properties.