By default if you install Sharepoint Foundation, Sql Server Express 2008 will be installed. Then you will face the 4 GB database size limit.
Not many people know that if you don’t want to pay for a full SQL server license and if you need more than 4GB, you can install SQL Server 2008 Express R2 (which provides up to 10 GB) OR you can use RBS.
The 10 GB limit was not part of the Community Preview release .
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