Methods, systems, and apparatus, including computer programs encoded on computer storage media, for serving encrypted and plain data from a low latency non-volatile memory. One of the methods includes executing a process on a server having a low latency volatile random access memory and a low latency non-volatile memory. The process is associated with an index file stored in the low latency volatile random access memory and encrypted and plain data stored in the low latency non-volatile memory. The process receives a query, finds data necessary to generate a response to the query using the index file, and retrieves the data from the low latency non-volatile memory whether the data is in an encrypted or a plain format. The process provides responses to queries where the responses are generated from a portion of either the encrypted data or the plain data stored in the low latency non-volatile memory.