Binary large object (BLOB) properties can be stored in two ways in the eXo JCR: in the database with items information or in an external storage on host file system. These options can be configured at workspace in the repository configuration file (repository-configuration.xml in portal and exo-jcr-config.xml in standalone mode). The database storage can't be completely disabled.

The first case is optimal for most of cases which you do not use very large values or/and do not have too many BLOBs. The configuration of the BLOBs size and BLOBs quantity in a repository depend on your database features and hardware.

The second case is to use an external values storage. The storage can be located on a built-in hard disk or on an attached storage. But in any cases, you should access to the storage as if it was a regular file(s). The external value storage is optional and can be enabled in a database configuration.