Performance study of data layout schemes for a SAN-based video server

Traditionally, network storage systems have mainly been dominated by two IP-based storage technologies, i.e., Network Attached Storage (NAS) and Storage Area Network (SAN). In recent years, cloud based storage (e.g., Amazon S3) has gained growing popularity for its high flexibility and cross-platform compatibility. Many enterprises are considering to replace traditional storage systems with cloud-based systems. Evaluating such a transition demands a systematic study on understanding the performance behaviours of the emerging cloud storage. To fill in this gap, in this paper, we conduct a comprehensive study on the three storage systems with realistic network conditions. Specifically, we select one representative from each category for comparison, i.e., Network File System (NFS) from NAS, Internet Small Computer System Interface (iSCSI) from SAN, and OpenStack Swift from cloud storage. We build a testbed and develop a suite of micro-benchmarks to study the impact of network complexities. Through a set of experiments and detailed analysis, we make several key observations: (1) iSCSI excels under good network conditions, e.g., in local area networks (LANs) where network delay and packet loss are trivial, (2) NFS and Swift are more suitable for complex networks such as wireless networks and Internet environment, (3) Swift is a viable replacement for NFS in all scenarios we investigate, and (4) system configuration on the client side impacts storage performance significantly and deserves adequate attention. We hope our findings can not only shed light on storage service design and optimizations, but also encourage more research on emerging storage technologies.

The ever-increasing demand for fast and reliable data storage has caused dramatic changes in the storage model. Direct attached storage (DAS) architecture, also known as server-centric architecture, is being replaced by the storage area network (SAN), leading to storage-centric architecture. In SAN storage devices exist completely independent of any computer (servers in particular). Multiple servers can access the same storage device without involvement of other servers. Recently, companies have been able to implement storage integration/sharing, remote backup/restoral, near-real-time disk mirroring/replication, and the like, using a new SAN architecture known as distributed storage area network (DSAN). The DSAN is multiple SANs interconnected using existing Internet Protocol (IP) networks to distribute storage over wide geographical areas. Even though DSANs provide additional capabilities to a SAN, the end-to-end latency (ETEL) due to large physical cable lengths (IP networks) imposes limitations on enterprise class application performance. DSANs can also be implemented using IP storage solutions that provide direct links between servers and storages, eliminating translation of fibre channel protocol frames to IP packets. This paper examines the effect of ETEL in DSAN on the performance of an enterprise class application with real-time application replication like Microsoft Exchange Server 2003. This investigation in done in two parts: disk subsystem (DS) characterization using Jetstress benchmarking software and the performance of Microsoft Exchange using LoadSim 2003 benchmarking software. Preliminary results were presented in [1].

The drive towards utilizing green and renewable energy to power large IT data centers is rapidly gaining momentum. Considerable research has gone into developing simulation models to comprehensively study the energy dynamics of different types of data center equipment in order to better understand how best to conserve it. Most of this research has gone towards modeling of servers and switches but relatively less amount of work is available on Storage Area Networks (SAN). Storage Area Networks play a very vital role in the data center architecture by using specialized storage hardware to manage data. In this paper, we have extended the Green Cloud simulator for computing the energy consumed by different SAN components. A simulation environment for SAN has been presented using the 'Dynamic Voltage and Frequency Scaling' (DVFS) and 'Dynamic Shutdown' (DNS) techniques. The simulation results obtained through two SAN prototype models shows the energy consumption of SAN components to vary with the network topology and type of technique used in scheduling of the workloads. Our experimental simulations revealed that there is an increasing percentage of energy savings in DNS mode for both topologies for an increasing number of servers. Results demonstrated up to 35.6% energy savings.

Storage area networks (SAN) technology has grown to meet the increasing storage requirements of businesses. The SAN concept was introduced to offer storage for multiple devices and applications. SAN are based on dedicated protocols such as fibre channel, which is designed to reduce the processing overheads on communications nodes. Business continuity is emerging as key application for SAN.

The ever increasing demand for fast and reliable data storage has caused dramatic changes in the storage model. The direct attached storage (DAS) model is being replaced by storage area networks (SANs). SANs provide the capability to distribute the storage across multiple servers leading to decentralized and externalized storage. Recently, the accessibility of SANs to small companies has been improved by using existing IP networks to distribute storage over long geographical distances, leading to the distributed storage area network (DSAN). Although DSANs have provided additional capabilities to SANs, they have created a new set of problems for enterprise class applications, like Microsoft Exchange Server 2003, with increasing end to end latency (ETEL), due to large physical cable lengths. We present an attempt to analyze the effect of ETEL in DSAN on the performance of Microsoft Exchange Server 2003 by monitoring the Exchange behavior using LoadSim 2003 benchmark.

Information storage is a central pillar of information technology. To enhance student awareness about Information Storage Technology, Storage Area Network (SAN) course was introduced for undergraduate students at VII semester level in Information Science & Engineering curricula. SAN deals with storing, managing, and protecting Digital Information in Classic, Virtualized, and Cloud Environments. EMC's open curriculum, aimed at addressing the knowledge gap that exists in the IT industry in the area of information storage and emerging technologies. The Storage Area Network (SAN)/Information Storage and Management (ISM) course proposed by EMC Academic Alliance is designed and developed to enable students to achieve a comprehensive understanding of all the segments of storage technology. Here SAN course was designed by considering EMC Academic Alliance course contents and framed Course Learning Objectives. Course activity was dedicated for the study and presentation of white papers on EMC products related to the concepts which they have studied. Industry visit to EMC Corporation was organized to gain knowledge about current storage technologies and how storage concepts are implemented in Data Center. At the end of the course, an EMC Proven Professional Certification online exam was conducted in our college. Through this course we have mapped some of the program outcomes with ABET criteria.

Due to the increasing amount of data handled by business applications and the need of an easy way to access data by multiple servers, storage area networks (SANs) have been proposed as a solution to be deployed in enterprises networks. Despite their advantages, a set of security issues are related to these next generation high speed network architectures and that may be a threat to the performance and the availability of such networks. In this paper, we propose an intrusion detection and tolerance system that ensures protection of the SANs against attacks. The proposed solution is based on: (a) the management of two areas (virtual area and protected area) at each storage node; (b) the cooperation of detection modules running on each SAN component; and (c) the use of distributed set of rules that are updated and managed in a secure manner. A case study is given to illustrate the proposed system capabilities in terms of intrusion detection and tolerance.

Design and performance evaluation of a metro WDM storage area network with IP datagram support

본 논문에서는 SAN(Storage Area Network)에 장착된 하드디스크를 단순히 고성능 저장장치로 교체하면 고성능 저장장치의 뛰어난 성능을 제대로 활용할 수 없음을 확인하고 원인 분석을 하여 고성능 저장장치를 위한 SAN의 성능 최적화기법들을 제안하였다. 먼저 고성능 저장장치에 맞지 않는 기존의 SAN 입출력경로에 존재하던 지연을 없애고, 저장장치 서버에서 입출력 요청들을 병렬 처리할 수 있게 하고, 소형 랜덤 입출력처리의 성능 향상을 위해 SAN에 연결된 초고속 네트워크에 사용되는 기존의 전송 프로토콜에 시간적 병합 기법을 추가하였다. 제안한 기법들의 우수성을 입증하는 방법으로 실제로 고성능 저장장치를 장착한 SAN에 최적화기법들을 구현하였으며, 다양한 입출력 데이터로 실험한 결과 30%이상의 입출력 지연시간 절감과 200%이상의 성능 향상을 확인하였다. We noted that substituting hard disk with high-performance storage device on SAN did not immediately result in getting high performance. Investigating the reason behind this leaded us to propose optimization schemes for high-performance storage system. We first got rid of the latency in the I/O process which is unsuitable for the high-performance storage device, added parallelism on the storage server, and applied temporal merge to Superhigh speed network protocol for improving the performance with small random I/O. The proposed scheme was implemented on the SAN with high-performance storage device and we verified that there were about 30% reduction on the I/O delay latency and 200% improvement on the storage bandwidth.

Storage Area Network (SAN) promise both a single source of data and improved performance and availability. SAN are extended to a WAN infrastructure to offer easier sharing over multiple locations. This created a need for bandwidth which can be provided by the underlying optical transport network. In this paper, we propose a policy-based lightpath signaling approach based on the OpenGrid architecture allowing SAN applications to dynamically establish and provision lightpaths over an optical network.

Storage area networks (SANs) are becoming an important part of optical metropolitan area networks (MANs). Growing storage and business-continuity needs; high-bandwidth, low latency requirements for SANs; storage infrastructure consolidation; and post-9/11 regulatory issues are among the several driving factors to push this trend. In this paper, we study network traffic in a proposed metro wavelength division multiplexing (WDM) ring architecture SAN with variable-length packets. The paper begins with a brief review of the relevant background information on SANs, data mirroring and network traffic analysis in the literature. Subsequently, the network architectures along with their medium access control (MAC) protocols are described. Network traffic analysis for the proposed network architectures is studied by means of discrete-event computer simulation. Network traffic characteristics are evaluated under self-similar asymmetric traffic scenarios.

SUMMARYThe proliferation of cloud services and other forms of service‐oriented computing continues to accelerate. Alongside this development is an ever‐increasing need for storage within the data centres that host these services. Management applications used by cloud providers to configure their infrastructure should ideally operate in terms of high‐level policy goals, and not burden administrators with the details presented by particular instances of storage systems. One common technology used by cloud providers is the Storage Area Network (SAN). Support for seamless scalability is engineered into SAN devices. However, SAN infrastructure has a very large parameter space: their optimal deployment is a difficult challenge, and subsequent management in cloud storage continues to be difficult.parindent = 10pt In this article, we discuss our work in SAN configuration middleware, which aims to provide users of large‐scale storage infrastructure such as cloud providers with tools to assist them in their management and evolution of heterogeneous SAN environments. We propose a middleware rather than a stand‐alone tool so that the middleware can be a proxy for interacting with, and informing, a central repository of SAN configurations. Storage system users can have their SAN configurations validated against a knowledge base of best practices that are contained within the central repository. Desensitized information is exported from local management applications to the repository, and the local middleware can subscribe to updates that proactively notify storage users should particular configurations be updated to be considered as sub‐optimal, or unsafe. Copyright © 2011 John Wiley & Sons, Ltd.

A novel artificial immune strategies based data storage model, called AIS-DS, is proposed for dealing with the problem of resources sharing in a storage area network (SAN). Especially for the multi-user's tasks, this technology has some essential features for ensuring the security and privacy of information and/or data, because a SAN here can be regarded exclusive for each user with its own vaccines (a kind of special codes assigned for this user), and on the other hand, damage or interference to the disk or type to some extent in a local area of SAN, will not destroy the integrity of the saved data. Furthermore, with AIS-DS, the privacy of user's coded/decoded data is guaranteed even if the disk is physically handed by some other unwanted users.

The Storage Area Network (SAN) is a space-saving storage technology to manage data securely. The amount of data that needs to be stored is growing, and this is due to the growing number of users of Information Technology all over the world. In this paper we will see what this technology is, the basic components that are involved in its construction, the protocols that are being used, and will address security issues in SAN.SAN, provides storage space management and maintains fast data up. Security has been and remains the top priority for any campaign that works with sensitive information and data, another element should be SANs. The vulnerability assessment is one of the critical requirements to make data storage a system safe. Knowledge about security elements and solutions can help data storage administrators to increase the security level and reliability of networks.

We describe the design, implementation and performance of a stand-alone media server. This server is intended to be used in voice over IP systems for audio interaction with users, NAT traversal, call monitoring and media recording. Its advantage is that it is application independent, which means that it can be used by any service and for any signaling protocol. In this paper we describe the design of the server, of its control protocol and of its functionalities such as file playing, DTMF detection, RTP proxying and audio recording. For file playing, we propose an approach to schedule RTP packet transmission that overcomes the irregularity of event scheduling of the operating system and for conversation recording, we propose an original approach to synchronize media streams that allows to avoid voice overlap while recording a conversation. We have conducted many experiments on the media server. We evaluated the accuracy of the file playing timing under different load conditions, the effect of the RTP proxying on the media quality and the subjective quality of recorded conversations. The results of these experiments show the great impact of the load of the media server on the performance of its functionalities, the improvement that the packet scheduling algorithm brings to the precision of inter-departure timing, and the good subjective quality of the recorded conversation using our synchronizing approach.