NASA Scientific and Technical Aerospace Reports

storage environment was upgraded to provide high availability, redundancy, and enhanced performance. This paper will
describe the resulting solution and lessons learned throughout the migration process.
Author
Data Management; Computer Programs; Redundancy
20040121027 European Organization for Nuclear Research, Geneva, Switzerland
Storage Resource Sharing with CASTOR
Baerring, Olof; Couturier, Ben; Durand, Jean-Damien; Knezo, Emil; Ponce, Sebastien; Motyakov, Vitaly; 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. 345-359; In English; See also 20040121020;
No Copyright; Avail: CASI; A03, Hardcopy
The Cern Advanced STORage (CASTOR) system is a hierarchical storage management system developed at CERN to
meet the requirements for high energy physics applications. The existing disk cache management subsystem in CASTOR, the
stager, was developed more than a decade ago and was intended for relatively moderate (large at the time) sized disk caches
and request load. Due to internal limitations a single CASTOR stager instance will not be able to efficiently manage distributed
disk cashes of several PetaBytes foreseen for the experiments at the Large Hadron Collider (LHC) which will be
commissioned in 2007. The Mass Storage challenge comes not only from the sheer data volume and rates but also from the
expected request load in terms of number of file opens per second. This paper presents the architecture design for a new
CASTOR stager now being developed to address the LHC requirements and overcome the limitations with the current
CASTOR stager. Efficient management of PetaByte disk caches made up of clusters of 100s of commodity file servers (e.g.
linux PCs) resembles in many aspects the CPU cluster management, for which sophisticated batch scheduling systems have
been available since more than a decade. Rather than reinventing scheduling and resource sharing algorithms and apply them
to disk storage resources, the new CASTOR stager design aims to leverage some of the resource management concepts from
existing CPU batch scheduling systems. This has led to a pluggable framework design, where the scheduling task itself has
been externalized allowing the reuse of commercial or open source schedulers. The development of the new CASTOR stager
also incorporates new strategies for data migration and recall between disk and tape media where the resource allocation takes
place just-in-time for the data transfer. This allows for choosing the best disk and network resources based on current load.
Author
Data Storage; Management Systems; Resource Allocation; Resources Management
20040121028 Rhode Island Univ., Kingston, RI, USA
Cost-Effective Remote Mirroring Using the iSCSI Protocol
Zhang, Ming; Liu, Yinan; Yang, Qing; 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. 385-398; In English; See also 20040121020
Contract(s)/Grant(s): NSF CCR-00-73377; NSF CCR-03-12613; No Copyright; Avail: CASI; A03, Hardcopy
This paper presents a performance study of the iSCSI protocol in the context of remote mirroring. We first integrate our
caching technology called DCD (disk caching disk) into a standard iSCSI target device to form a high performance storage
system for mirroring purpose. Performance measurements are then carried out using this storage system as well as standard
iSCSI targets as mirroring devices. We consider remote mirroring on a LAN (local area network) and on a commercial WAN
(wide area network). The workloads used in our measurements include popular benchmarks such as PostMark and IoMeter,
and real-world I/O traces. Our measurement results show that iSCSI is a viable approach to cost-effective remote mirroring
for organizations that have moderate amount of data changes. In particular, our DCD-enhanced iSCSI target can greatly
improve performance of remote mirroring.
Author
Protocol (Computers); Local Area Networks; Wide Area Networks; Cost Effectiveness
20040121029 BlueArc Corp., San Jose, CA, USA
Multi-Tiered Storage: Consolidating the Differing Storage Requirements of the Enterprise Into a Single Storage
System
Gray, Louis; 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. 427-432;
In English; See also 20040121020; No Copyright; Avail: CASI; A02, Hardcopy
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