• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.359-366
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• 2001

This paper overviews the design of SANique$^{TM}$ -a shred file system for Linux cluster based on SAN environment. SANique$^{TM}$ has the capability of transferring user data from network-attached SAN disks to client applcations directly without the control of centralized file server system. The paper also presents the characteristics of each SANique$^{TM}$ subsystem: CFM(Cluster File Manager), CVM(Cluster Volume Manager), CLM(Cluster Lock Manager), CBM(Cluster Buffer Manager) and CRM(Cluster Recovery Manager). Under the SANique$^{TM}$ design layout, then, the syndrome of '||'&'||'quot;split-brain'||'&'||'quot; in shared file system environments is described and defined. The work first generalizes and illustrates possible situations in each of which a shared file system environment may split into two or more pieces of separate brain. Finally, the work describes the SANique$^{TM}$ approach to the given "split-brain"problem using SAN disk named "split-brain" and develops the overall recovery procedure of shared file systems.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.11-25
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• 2020

This study proposes a method to manipulate fragmentation of disks by arbitrarily allocating and releasing the status of a disk cluster in the NTFS file system. This method allows experiments to be performed in several studies related to fragmentation problems on disk cluster. Typical applicable research examples include testing the performance of disk defragmentation tools according to the state of fragmentation, establishing an experimental environment for fragmented file carving methods for digital forensics, setting up cluster fragmentation for testing the robustness of data hiding methods within directory indexes, and testing the file system's disk allocation methods according to the various version of Windows. This method suggests how a single file occupies a cluster and presents an algorithm with a flowchart. It raises three tricky problems to solve the method, and we propose solutions to the problems. Experiments for allocating the disk cluster to be fragmented to the maximum extent possible, it then performs a disk defragmentation experiment to prove the proposed method is effective.

• Journal of Information Technology Services
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• v.7 no.1
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• pp.195-204
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• 2008

As the dependency to network system and demands of efficient storage systems rapidly grows in every networking filed, the current trends initiated by explosive networked data grow due to the wide-spread of internet multimedia data and internet requires a paradigm shift from computing-centric to data-centric in storage systems. Furthermore, the new environment of file systems such as SAN(Storage Area Network) is adopted to the existing storage paradigm for providing high availability and efficient data access. We describe the design issues and system components of $SANique^{TM}$, which is the cluster file system based on SAN environment. We, especially, present the comparative results of performance analysis for the intensive I/O test by using the DBMSs that are operated at the top of cluster file system $SANique^{TM}$, EXT3 and NFS respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.415-420
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• 2010

This paper describes the design overview of shared file system $SANique^{TM}$ and analyzes the performance evaluation results of I/O intensive stress test based on various cluster file system architectures. Especially, we illustrate the performance analysis for the comparison results between the $SANique^{TM}$ and the Linux file system EXT3 system that is used to generally in Unix world. In order to perform our evaluation, Oracle 10g database system is operated on the top of cluster file system, and we developed the various kinds of testing tools which are compiled by ESQL/C from Oracle. Three types of architectures are used in this performance evaluation. Those are the cluster file system $SANique^{TM}$, EXT3 and the combined architecture of $SANique^{TM}$ and EXT3. In this paper, we present that the results of $SANique^{TM}$ outperforms other cluster file systems in the overhead for providing the true sharing over the connecting server nodes.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.178-192
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• 2021

File system forensics typically focus on the contents or timestamps of a file, and it is common to work around file/directory centers. But to recover a deleted file on the disk or use a carving technique to find and connect partial missing content, the evidence must be analyzed using cluster-centered analysis. Forensics tools such as EnCase, TSK, and X-ways, provide a basic ability to get information about disk clusters, but these are not the core functions of the tools. Alternatively, Sysinternals' DiskView tool provides a more intuitive visualization function, which makes it easier to obtain information around disk clusters. In addition, most current tools are for Windows. There are very few forensic analysis tools for MacOS, and furthermore, cluster analysis tools are very rare. In this paper, we developed a tool named FACT (Forensic Analyzer based Cluster Information Tool) for analyzing the state of clusters in a HFS+ file system, for digital forensics. The FACT consists of three features, a Cluster based analysis, B-tree based analysis, and Directory based analysis. The Cluster based analysis is the main feature, and was basically developed for cluster analysis. The FACT tool's cluster visualization feature plays a central role. The FACT tool was programmed in two programming languages, C/C++ and Python. The core part for analyzing the HFS+ filesystem was programmed in C/C++ and the visualization part is implemented using the Python Tkinter library. The features in this study will evolve into key forensics tools for use in MacOS, and by providing additional GUI capabilities can be very important for cluster-centric forensics analysis.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.241-252
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• 2006

In cluster file systems, the availability of files has been supported by replicating entire files or generating parities on parity servers. However, those methods require very large temporal and spatial cost, and cannot handle massive failures situation on the file system. So we propose HA-PVFS, a cluster file system supporting high data availability adaptive to temporal locality. HA-PVFS restricts replication or parity generation to some important files, for that it employs an efficient algorithm to estimate file access patterns from limited information. Moreover, in order to minimize the performance degradation of the file system, it uses delayed update method and relay replication.

• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.505-517
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• 2004

This paper overviews the design details of the cluster file system $\textrm{SANique}^{TM}$ on the SAN environment. $\textrm{SANique}^{TM}$ has the capability of transferring user data from shared SAN disk to client application without control of centralized file server. We, especially, focus on the characteristics and functions of recovery manager CRM of $\textrm{SANique}^{TM}$. The process component for failure detection and its overall procedure are described. We define the split-brain problem that cannot be easily detected in cluster file systems and also propose the recovery management method based on SAN disk in order to detect and solve the split-brain situation.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.547-549
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• 2007

Recently with increasing the use of parallel computing and cluster system which was connected high speed network, the interest about distributed and parallel file system is increasing. Specially, there are many researches, which focused on optimizing the performance of distributed and parallel file system for the more efficient use of cluster system. In this paper, we analyzed the performance of PVFS(Parallel Virtual File System) in small cluster system. In addition, to improve the PVFS performance we proposed the chancing the size of flow buffer according to the network speed and we optimized the PVFS performance on small cluster system.

• The Transactions of the Korea Information Processing Society
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• v.3 no.3
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• pp.617-630
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• 1996

In this paper, a shared-concurrent file system (S-CFS) is designed and implemented using conventional disks as disk arrays on a Workstation Cluster which can be used as a small-scale server. Since it is implemented on UNIX operating systems, S_CFS is not only portable and flexible but also efficient in resource usage because it does not require additional I/O nodes. The result of the research shows that on small-scale systems with enough disks, the performance of the concurrent file system on transaction processing applications is bounded by the bottleneck of CPUs computing powers while the performance of the concurrent file system on massive data I/Os is bounded by the time required to copy data between buffers. The concurrent file system,which has been implemented on a Workstation Cluster with 8 disks,shows a throughput of 388 tps in case of transaction processing applications and can provide the bandwidth of 15.8 Mbytes/sec in case of massive data processing applications. Moreover,the concurrent file system has been dsigned to enhance the throughput of applications requirring high performance I/O by controlling the paralleism of the concurrent file system on user's side.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2404-2410
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• 2011

This paper describes the design overview of cluster file system $SANique^{TM}$ based on SAN(Storage Area Network) environment. The design issues and problems of the conventional global buffer manager are also illustrated under a large set of clustered computing hosts. We propose the efficient global buffer management method that provides the more scalability and availability. In our proposed global buffer management method, we reuse the maintained list of lock information from our cluster lock manager. The global buffer manger can easily find and determine the location of requested data block cache based on that lock information. We present the pseudo code of the global buffer manager and illustration of global cache operation in cluster environment.