In this paper we look at the performance characteristics of three tools used to move large data sets over dedicated long distance networking infrastructure. Although performance studies of wide area networks have been a frequent topic of interest, performance analyses have tended to focus on network latency characteristics and peak throughput using network traffic generators. In this study we instead perform an end-to-end long distance networking analysis that includes reading large data sets from a source file system and committing the data to a remote destination file system. An evaluation of end-to-end data movement is also an evaluation of the system configurations employed and the tools used to move the data. For this paper, we have built several storage platforms and connected them with a high performance long distance network configuration. We use these systems to analyze the capabilities of three data movement tools: BBcp, GridFTP, and XDD. Our studies demonstrate that existing data movement tools do not provide efficient performance levels or exercise the storage devices in their highest performance modes.

Obtaining consistent bandwidth with predictable latency from disk-based storage systems has proven difficult due to the storage system's inability to understand quality of service (QoS) requirements. In this paper, we present a feasibility study of QoS with the object-based storage device (OSD) specification. We look at OSD's ability to provide QoS guarantees for consistent bandwidth with predictable latency. Included in this paper is a description of QoS requirements of a sample application and how these requirements are translated into parameters that are then communicated to, and interpreted by, the OSD. Implementation problems lead to the failure of a hard real-time QoS model, but this failure is not due to the OSD protocol. The paper concludes with a description of how well the revision 9 OSD standard (OSDR9) is able to accommodate QoS. We provide suggestions for improving the OSD specification and its ability to communicate QoS requirements.

Quality of service (QoS) is crucial for certain applications such as multimedia. As the object-based storage device (OSD) protocol emerges as the next generation storage technology, QoS provisioning for OSD-based systems has also received a great deal of attention. In this paper, we propose a QoS framework for OSD-based storage system that integrates both the network QoS and storage QoS. We examine the existing OSD specification and analyze the QoS requirements for applications on OSD clients. Based on the QoS requirements analysis, we propose a three-level QoS specification. We further elaborate on extensions to the existing OSD and iSCSI protocol to support our QoS specification. These extensions are then incorporated with the current OSD reference implementation. Finally, we discuss both the implementation structure and issues encountered as part of this study.

This paper describes a simple but effective method to generate and observe the effects of external vibration on the read and write bandwidth of a disk drive. Furthermore, it quantifies these effects as a first-order numerical approximation. This paper is not intended to rate disk drives relative to manufacturer, model, size, form factor, etc. Rather it is simply intended to answer the simple questions of "Is there a performance impact of external vibration on a disk drive?" and "How significant is that impact?" After testing several 3.5- and 2.5-inch consumer-grade and enterprise-class disk drives the conclusion is that the consumer-grade disk drives are more sensitive to external vibration. In the presence of an external vibration caused by adjacent disk drive seek operations the bandwidth performance of a consumer-grade disk drive "feeling" these vibrations will decrease about 10%-15% when reading data and about 25%-40% when writing data. The final qualitative result of this study is that disk drive packaging is likely the most significant factor in reducing the vibrational effects.