From the architecture overview; they need 7 GB of memory to index 100 million objects. That's over 75 bytes per object, which is quite a lot. To be able to gua

From the architecture overview; they need 7 GB of memory to index 100 million objects. That's over 75 bytes per object, which is quite a lot. To be able to guarantee maximum 1 disk access, they would need to store the hash, the address, and the size. You can do that naively by using 160 bits for SHA1, 64 bits for address and 32 bits for size, which is only 32 bytes. Maybe they use the rest for metadata like generation count... http://citrusleaf.net/_docs/Architecture_Overview.pdf http://citrusleaf.net/_docs/Architecture_Overview.pdf