Jumbo Store: Providing Efficient Incremental Upload and Versioning for a Utility Rendering Service

Abstract

We have developed a new storage system called the Jumbo Store (JS) based on encoding directory tree snapshots as graphs called HDAGs whose nodes are small variable-length chunks of data and whose edges are hash pointers. We store or transmit each node only once and encode using landmark-based chunking plus some new tricks. This leads to very efficient incremental upload and storage of successive snapshots: we report compression factors over 16x for real data; a comparison shows that our incremental upload sends only 1/5 as much data as Rsync. To demonstrate the utility of the Jumbo Store, we have integrated it into HP Labs ’ prototype Utility Rendering Service (URS), which accepts rendering data in the form of directory tree snapshots from small teams of animators, renders one or more requested frames using a processor farm, and then makes the rendered frames available for download. Efficient incremental upload is crucial to the URS’s usability and responsiveness because of the teams ’ slow Internet connections. We report on the JS’s performance during a major field test of the URS where the URS was offered to 11 groups of animators for 10 months during an animation showcase to create high-quality short animations.