To reduce the database entry size, the existing database entry format is changed. The internal representation of an entry changed from an ASCII LDIF format to a tagged binary format. The data stored in the database does not have the characteristic starting of dn: anymore, the first byte of an entry being a value bigger than 0xE0 (hence all values 0xE0 to 0xFF are to be considered reserved for internal use).
For compatibility reasons entries can be a mix of LDIF and binary representations, but any modification will write the entry in binary format.
Suffix entries data can be compressed when written to disk to minimize their disk footprint. Compression is enabled according to the settings of the compression-mode and compression-entries properties,
For additional information, refer to the Chapter 8, Writing Entry Store and Entry Fetch Plug-Ins, in Sun Directory Server Enterprise Edition 7.0 Developer’s Guide.