Asterisk: The Future of Telephony, 2nd Edition

ODBC Voicemail

Asterisk contains the ability to store voicemail inside the database using the ODBC connector. This is useful in a clustered environment where you want to abstract the voicemail data from the local system so that multiple Asterisk boxes have access to the same data. Of course, you have to take into consideration that you are centralizing a part of Asterisk, and you need to take actions to protect that data, such as regular backups, and possibly clustering the database backend using replication. If you are using PostgreSQL, there are some good projects for doing this: PGcluster (http://pgfoundry.org/projects/pgcluster/) and Slony-I (http://gborg.postgresql.org/project/slony1/projdisplay.php).

Asterisk stores the voicemail inside a Binary Large Object (BLOB). When retrieving the data, it pulls the information out of the BLOB and temporarily stores it on the hard drive while it is being played back to the user. Asterisk then removes the BLOB and records from the database when the user deletes the voicemail. Many databases, such as MySQL, contain native support for BLOBs, but PostgreSQL has a couple of extra steps required to utilize this functionality that we’ll explore in this section. When you’re done, you’ll be able to record, play back, and delete voicemail data from the database just as if it were stored on the local hard drive.

Note

This section builds upon previous configuration sections in this chapter. If you have not already done so, be sure to follow the steps ...