Promote-IT: An efficient Real-Time Tertiary-Storage Scheduler

Promote-IT is an efficient heuristic scheduler that provides QoS guarantees for accessing data from tertiary storage. It can deal with a wide variety of requests and jukebox hardware. It provides short response and confirmation times, and makes good use of the jukebox resources. It separates the scheduling and dispatching functionality and effectively uses this separation to dispatch tasks earlier than scheduled, provided that the resource constraints are respected and no task misses its deadline. To prove the efficiency of Promote-IT we implemented alternative schedulers based on different scheduling models and scheduling paradigms. The evaluation shows that Promote-IT performs better than the other heuristic schedulers. Additionally, Promote-IT provides response-times near the optimum in cases where the optimal scheduler can be computed

Continuous Data Management on Tape-Based Tertiary Storage Systems

. Video-on-Demand (VOD) servers are becoming feasible. These servers have voluminous data to store and manage. A tape-based tertiary storage system seems to be a reasonable solution to lowering the cost of storage and management of this continuous data. In this paper we address the issues of decomposing and placing continuous data blocks on tapes, and the scheduling of multiple requests for materializing objects from tapes to disks. We first study different policies for continuous object decomposition and blocks placement on tapes under different characteristics of the tertiary storage drives. Afterwards, we propose a scheduling algorithm for object materialization. 1 Introduction Most multimedia data is currently stored on magnetic hard disks, yet the proliferation of such applications is generating massive amounts of data such that a storage subsystem based solely on hard disks will be too expensive to support and manage. The video-on-demand (VOD) server is one particular multimedia..