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iSCSI is a network storage technology designed to provide an economical solution over a TCP/IP Network. This paper presents a new iSCSI design with multiple TCP/IP connections. The prototype is developed and experiments are conducted for performance evaluation on Gigabit Ethernet (GE). Test results show that the new iSCSI design improves performanc...
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... results are analyzed and discussed. Figure 1 shows an iSCSI storage architecture including an initiator and a target, which communicate to each other via the iSCSI protocol. In the initiator, the application, which needs to store and access data to/from the storage device, issues file requests. ...
Citations
... In consequence, schools should give more preferential policies and encourage teachers with strength to spare to develop excellent microlearning resources and PPT documents and video data, realizing real-time update with the help of WeChat. [4][5] When developing micro-learning resources, teachers should pay attention to the standardization of text and images on learning Fund project: College students' training program on innovation and entrepreneurship in universities of Tianjin "Exploration on Influence of Micro-culture on College Students' Learning Behavior and Career Choice Behavior" (201510061115) *Corresponding author: Li Wang, research assistant, research direction: higher education management. Qin Zou, undergraduate in school of basic science of Tianjin Agricultural University materials and strengthening interestingness, so as to arouse students' learning interest and enthusiasm. ...
... Our implementation of the iSCSI target is similar to UNH iSCSI implementation [24] built on top of the TCP/IP stack, as shown in Fig. 2. There has been research in the literature on the iSCSI protocol including storage implementations [24], [25], [26], [27], performance evaluations using simulations [33], [28] and measurements [29], [30], [31]. It has been shown in these studies that iSCSI performs very well as a block-level data storage. ...
This paper presents a comprehensive study on implementations and performance evaluations of two snapshot techniques: copy-on-write snapshot and redirect-on-write snapshot. We develop a simple Markov process model to analyze data block behavior and its impact on application performance, while the snapshot operation is underway at the block-level storage. We have implemented the two snapshots techniques on both Windows and Linux operating systems. Based on our analytical model and our implementation, we carry out quantitative performance evaluations and comparisons of the two snapshot techniques using IoMeter, PostMark, TPC-C, and TPC-W benchmarks. Our measurements reveal many interesting observations regarding the performance characteristics of the two snapshot techniques. Depending on the applications and different I/O workloads, the two snapshot techniques perform quite differently. In general, copy-on-write performs well on read intensive applications, while redirect-on-write performs well on write intensive applications.
... Since most of these protocols are in the prototyping stage, their performance characteristics have not yet been studied. Currently there are efforts underway to examine the overhead of iSCSI in various contexts [1,30,39,27,15]. Since there is no clear understanding of the overheads associated with iSCSI and to better control various system parameters, in this work we perform our own experiments with a commodity iSCSI setup. ...
This work presents a Vl-attached database storage architecture to improve database transaction rates. More specifically, we examine how Vl-based interconnects can be used to improve I/O path performance between a database server and a storage subsystem. To facilitate the interaction between client applications and a Vl-aware storage system, we design and implement a software layer called DSA, that is layered between applications and VI. DSA takes advantage of specific VI features and deals with many of its shortcomings. We provide and evaluate one kernel-level and two user-level implementations of DSA. These implementations trade transparency and generality for performance at different degrees and, unlike research prototypes, are designed to be suitable for real-world deployment. We have also investigated many design trade offs in the storage cluster. We present detailed measurements using a commercial database management system with both microbenchmarks and industrial database workloads on a mid-size, 4 CPU, and a large, 32 CPU, database server. We also compare the effectiveness of Vl-attached storage with an iSCSI configuration, and conclude that storage protocols implemented using DSA over VI have significant performance advantages. More generally, our results show that Vl-based interconnects and user-level communication can improve all aspects of the I/O path between the database system and the storage back-end. We also find that to make effective use of VI in I/O intensive environments, we need to provide substantial additional functionality than what is currently provided by VI. Finally, new storage APIs that help minimize kernel involvement in the I/O path are needed to fully exploit the benefits of Vl-based communication.
... Recently, and due to the increasing importance of scaling storage subsystems and reducing system costs, there have been a number of efforts to build efficient iSCSI implementations and also to evaluate various aspects of iSCSI. A number of iSCSI implementations are currently available [3, 8, 19, 12, 1, 9, 4, 25]. As mentioned in our work we use [3] after examining most of the publicly available systems. ...
iSCSI is proposed as a possible solution to building future stor- age systems. However, using iSCSI raises numerous questions about its implications on system performance. This lack of un- derstanding of system I/O behavior in modern and future systems inhibits providing solutions at the architectural and system levels. Our main goals in this work are to understand the behavior of the application server (iSCSI initiator), to evaluate the overhead introduced by iSCSI compared to systems with directly-attached storage, and to provide insight about how future storage systems may be improved. We examine these questions in the context of commodity iSCSI systems that can benefit most from using iSCSI. We use commodity PCs with several disks as storage nodes and a Gigabit Ethernet network as the storage network. On the application server side we use a broad range of benchmarks and applications to evaluate the impact of iSCSI on application and server performance. We instrument the Linux kernel to provide detailed information about I/O activity and the various overheads of kernel I/O layers. Our analysis reveals how iSCSI affects application perfor- mance and shows that building next generation, network-based I/O architectures, requires optimizing I/O latency, reducing net- work and buffer cache related processing in the host CPU, and increasing the sheer network bandwidth to account for consolida- tion of different types of traffic.
... The ability of an iSCSI session to span multiple connections is used in [XION04] to develop a higher performance solution. An experiment was performed over a metropolitan network and multiple virtual connections were opened over a single physical connection. ...
... The results show that multiple connections can allow the gigabit metro network to achieve speeds of 97-107 MB/s [XION04]. It was also discovered that high throughputs result in higher CPU utilizations (a claim that experiments conducted at HCS-Tallahassee can verify). ...
For a number of years, high performance disaster recovery networks have been unavailable to all but the largest and wealthiest organizations. However, a recently adopted IETF standard known as iSCSI promises to not only provide performance comparable to the best disaster recovery solutions but also extend the availability of these solutions to home and small office environments.
This paper will explore the details of iSCSI and illustrate how it can provide a cost effective and high performance solution to disaster recovery and business continuity operations. A software-based iSCSI implementation is tested to determine whether it can perform at gigabit and higher speeds and what CPU utilization is required to operate the software drivers. If iSCSI can perform well in software then it is reasonable to assume that it can perform as well or better when realized in hardware. It will be shown that iSCSI can perform as well as the best Fibre Channel networks available at a reduced cost. Finally, a number of modifications will be proposed that will enhance the effectiveness of iSCSI as a disaster recovery mechanism.
Multiple network cards and multiple connections in iSCSI are important ways to improve iSCSI systems performance, fault tolerance and scalability. But multiple connections technology cannot assign every task appropriately, so it cannot produce the excellent performance. This paper proposes a dynamic load balancing algorithm using a feedback control mechanism to improve the overall performance in iSCSI systems. In order to adjust the load state dynamically, this algorithm adopts a feedback mechanism to calculate multiple resources states that have been collected in this system, and then combines the results and the previous feedback. The test results indicate that with the help of this algorithm the performance of iSCSI system has been improved.
While snapshots have been commonly used in data storages for backup and data protections, little is known in the open literature how such snapshots impact application performance. This paper presents an implementation and performance evaluation of two snapshot techniques: copy-on-write snapshot and redirect-on-write snapshot. Our implementation is carried out at block level on a standard iSCSI target. We carry out quantitative performance evaluations and comparisons of the two snapshot implementations using TPC-C, TPC-W, IoMeter, and PostMark benchmarks. Our measurements reveal many interesting observations regarding the performance characteristics of the two snapshot techniques. Depending on the applications and different I/O workloads, the two snapshot techniques perform quite differently. In general, copy-on-write performs well on read-intensive applications while redirect-on-write performs well on write-intensive applications.
The function of current multimedia instruction monitor system is only limited to essential teaching activity. It uses mostly dasiascreen surveillancepsila to monitor the student computer, and limit their activity by locking the screen. But it could do nothing for ones who copy files through network neighbor or mobile storage media which could be done within minutes or even seconds. It is also useless when student escape monitor by unplugging network connection line. In this article, an effective solution is given which is based on windows Hook and multithread technique. Using Hook track the keyboard and mouse operation; extract and examine the characters of the focused-on window and mobile storage media using information obtained from the tracking. Stop the message transmitting for the operation suspected of copying, or clear the clipboard to invalidate the operation of copying. For the user who unplugged the network connection line for escaping monitor, freeze the screen, lock the keyboard immediately. When the network connection restored, defreeze the screen and unlock the keyboard automatically. So, that becomes offline intelligent monitor. This article gives a brief description of the system design and detail of the algorithm, which is used in the practice of instruction. It is proved from both theory and practice that the technical solution is advanced and reliable, it fills up the blank of the anti-copy and plagiarism in multimedia instruction monitoring system.
