The transaction log for database 'SharePoint_Config' is full

Scenario: Tried to change web application settings from Authentication Providers page from Central Administration

Problem: Received the error "The transaction log for database 'SharePoint_Config' is full" when tried to save the updated settings.

Resolution: Found that the drive that containing the config database log is having very few space remaining.

Following steps helped to resolve this issue

1. Do full backups of all the SharePoint databases.  

2. Open the database, right click SharePoint Config database > Properties

3. Select Simple under Recovery model list > Click OK

4. Right click the database,  Tasks > Shrink > Files

5. In File type select Log

6. Click OK

Refer to the following post for more information

http://alstechtips.blogspot.com/2011_04_07_archive.html

Fuente:

http://sharepointserved.blogspot.com