17. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computer system with one or more processors, cause the computer system to: group a set of documents into a plurality of clusters, wherein each cluster includes one or more documents of the set of documents and a respective cluster of the plurality of clusters includes a plurality of documents including a first document and a second document; compress the plurality of documents in the respective cluster to generate compressed cluster data, wherein compressing the plurality of documents includes: determining that the second document includes duplicate data that is duplicative of corresponding data in the first document; eliding the duplicate data from compressed cluster data; and storing document data from which the first document and the second document can be reconstructed, the document data including document reconstruction data; and generate an index of the compressed cluster data.
18. The non-transitory computer readable storage medium of claim 17 , wherein a respective cluster of the plurality of clusters includes a plurality of documents that are determined to be related to each other.