NASA Scientific and Technical Aerospace Reports

in offloading significant management overhead and complexity from higher system layers to the disk itself and is a concrete
step towards building self-managed storage devices. Our specific contributions are: (i) We implement Clotho as a new layer
in the block I/O hierarchy in Linux and demonstrate that versioning can be performed at the block level in a transparent
manner. (ii)We investigate the impact on I/O path performance overhead using both microbenchmarks as well as SPEC SFS
V3.0 over two real filesystems, Ext2FS and ReiserFS. (iii) We examine techniques that reduce the memory and disk space
required for metadata information.
Author
File Maintenance (Computers); Unix (Operating System); Data Storage; Data Management
20040121043 Minnesota Univ., Minneapolis, MN, USA
An Efficient Data Sharing Scheme for iSCSI-Based File Systems
He, Ding-Shan; Du, David H. C.; NASA/IEEE MSST 2004 Twelfth NASA Goddard Conference on Mass Storage Systems
and Technologies in cooperation with the Twenty-First IEEE Conference on Mass Storage Systems and Technologies; April
2004, pp. 233-237; In English; See also 20040121020; No Copyright; Avail: CASI; A01, Hardcopy
iSCSI is an emerging transport protocol for transmitting SCSI storage I/O commands and data blocks over TCP/IP
networks. It allows storage devices to be shared by multiple network hosts. A fundamental problem is how to enable consistent
and efficient data sharing in iSCSI-based environments. In this paper, we propose a suite of data sharing schemes for
iSCSI-based file systems and use ext2 as an example for implementation. Finally, we use simulations to verify the correctness
of our designs and to study the performances.
Author
Data Storage; Computer Networks; Computer Storage Devices; Metadata
20040121051 Minnesota Univ., Minneapolis, MN, USA
Simulation Study of iSCSI-Based Storage System
Lu, Ying-Ping; Noman, Farrukh; Du, David H. C.; NASA/IEEE MSST 2004 Twelfth NASA Goddard Conference on Mass
Storage Systems and Technologies in cooperation with the Twenty-First IEEE Conference on Mass Storage Systems and
Technologies; April 2004, pp. 399-407; In English; See also 20040121020; No Copyright; Avail: CASI; A02, Hardcopy
iSCSI is becoming an important protocol to enable remote storage access through the ubiquitous TCP/IP network. Due
to the significant shift in its transport mechanism, iSCSI-based storage system may possess different performance
characteristics from the traditional storage system. Simulation offers a flexible way to study the iSCSI-based storage system.
In this paper, we present a simulation work of iSCSI-based storage system based on ns2. The storage system consists of an
iSCSI gateway with multiple targets, a number of storage devices that are connected to the storage router through FC-AL and
clients, which access the target through iSCSI protocol. We present the system model, the implementation of the components,
the validation of the model and performance evaluation based on the model. Coupled with the rich TCP/IP support from ns2,
the simulation components can be effortlessly used for the performance and alternatives study of iSCSI-based storage systems,
applications in broad configurations.
Author
Computer Systems Simulation; Data Storage
20040121052 Patuxent Technology Partners, LLC, Fairfax Station, VA, USA
SAN and Data Transport Technology Evaluation at the NASA Goddard Space Flight Center (GSFC)
Thompson, Hoot; NASA/IEEE MSST 2004 Twelfth NASA Goddard Conference on Mass Storage Systems and Technologies
in cooperation with the Twenty-First IEEE Conference on Mass Storage Systems and Technologies; April 2004, pp. 119-138;
In English; See also 20040121020; No Copyright; Avail: CASI; A03, Hardcopy
Growing data stockpiles and storage consolidation continue to be the trend. So does the need to provide secure yet
unconstrained, high bandwidth access to such repositories by geographically distributed users. Conventional data management
approaches, both at the local and wide area level, are viewed as potentially inadequate to meet these challenges. This paper
explores methods deploying a new breed of Fibre Channel (FC) technology that leverages Internet Protocol (IP) infrastructures
as the data transport mechanism, a step towards creating a ‘storage area network (SAN) grid". These technologies
include products using the FC Over IP (FCIP) and the Internet FC Protocol (iFCP) protocols. The effort draws upon earlier
work that concentrated on standard FC and internet SCSI (iSCSI) technologies. In summary, the vendor offerings tested
performed as expected and provided encouraging performance results. However, their operational readiness still needs to be
understood and demonstrated. Installing and configuring the products was reminiscent of the early days of FC with driver and
236