100GB is not the limit, its actually a best practise. This post lists out few suggestions. The following represents Microsoft's guidance and best practices on content databases, as specified in various places on technet.microsoft.com:
- Limit the content database size to 100GB; use multiple content databases if necessary.
- Create multiple data files and spread them across multiple disks; only create files in the primary file group.
- The number of data files should be less than or equal to the number of core CPUs; count dual core processors as two CPUs; count each processor that supports hyper-threading as one CPU.
- Create data files of equal size.
- Consider using SQL Server backup and restore; the SharePoint built-in tools can only restore files to the backup location.