cdb - 大文件的常量键值存储（数百GB）

I need a tool similar to cdb (constant database) that would allow me to store large sets of data (in the range of hundreds of gigabytes) in indexed files. CDB is an ideal candidate but it has a 2 GB file size limit so it's not suitable. The functionality I'm looking for is a persistent key-value store supporting binary keys and values. After creating the database is read only and will never be modified. Can you recommend some tool? And btw, storage overhead should be small because I will be storing billion of records.I need a tool similar to cdb (constant database