• The KIPS Transactions:PartA
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• v.10A no.2
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• pp.123-130
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• 2003

This paper presents a new striped checkpointing scheme for serverless cluster computers, where the local disks are attached to the cluster nodes collectively form a distributed RAID with a single I/O space. Striping enables parallel I/O on the distributed disks and staggering avoids network bottleneck in the distributed RAID. We demonstrate how to reduce the checkpointing overhead and increase the availability by striping and staggering dynamically for communication intensive applications. Linpack HPC Benchamark and MPI programs are applied to these checkpointing schemes for performance evaluation on the 16-nodes cluster system. Benchmark results prove the benefits of the striped checkpointing scheme compare to the existing schemes, and these results are useful to design the efficient checkpointing scheme for fast rollback recovery from any single node failure in a cluster system.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.27-29
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• 1999

RAID는 고병렬성과 고가용성을 목표로 제안된 대용량 저장 수단이다. 패리티 디클러스터링을 이용한 RAID는 특히 고장이 발생한 경우에도 성능의 저하를 최소화하여 고가용성을 갖는 저장장치를 구축할 수 있는 기법이다. 본 논문에서는 이러한 패리티 디클러스터링을 사용한 RAID에 스페어 유닛을 분산시킨 구성을 제안하고, 특히 이러한 분산 스페어링이 고장이 없는 정상 상태에서도 성능 개선에 유용함을 보인다. 본 논문의 실험 결과는 시뮬레이션 방식으로 입증하였으며, 전반적으로 정상상태의 성능을 5-15% 정도 높일 수 있음을 알 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.497-506
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• 2000

RAID systems have been used as a mass storage system with high parallelism and availability. Especially RAID systems with parity declustering are widely studied as a technique to provide high fault tolerancy and availability by reducing performance degradation in case of disk fuilures. In this paper, a new organization of parity declustering with distributed spare units is proposed. And in normal mode where there are no failures, it is shown that these organization can improve the performance of RAID systems. By simulation methods, it is proved that the performance of RAID system in normal mode is improved by 5 to 15%.

• Smart Media Journal
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• v.5 no.1
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• pp.69-77
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• 2016

This paper proposes a software defined storaging method to converge the network virtualization technique and the RAID of distributed storage environment. The proposed method designs software based storage which it apply a flexible control and maintenance of storages. In addition, the method overcomes the restricted of physical storage capacity and cut costs of data recovery. The proposed failover recovery technique based on Software-Defined RAID has been tested the substantial verification and the performance using public AWS and Google Storage.

• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.607-614
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• 2006

The checkpointing schemes should reduce the process delay through managing the checkpoints of each node to fit the network load to enhance the performance of the process running on the cluster system that write the checkpoints into its global stable storage. For this reason, a cluster system with single IO space on a distributed RAID chooses a suitable checkpointng scheme to get the maximum IO performance and the best rollback recovery efficiency. In this paper, we improved the striped checkpointing scheme with dynamic stripe group size by adapting to the network bandwidth variation at the point of checkpointing. To analyze the performance of the multi striped checkpointing scheme, we applied Linpack HPC benchmark with MPI on our own cluster system with maximum 512 virtual nodes. The benchmark results showed that the multistriped checkpointing scheme has better performance than the striped checkpointing scheme on the checkpoint writing efficiency and rollback recovery at heavy system load.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.64-66
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• 2004

단일 입출력 디스크(SDIO)는 클러스터 환경에서 빠르고 신뢰성 있는 분산 저장장치를 제공한다. 단일 입출력 디스크는 주로 RAID 레벨 0이나 레벨 1을 사용하는데, RAID 레벨 5를 사용함으로써 좋은 성능과 좋은 신뢰도 그리고 높은 디스크 용량 사용률을 얻을 수 있다. 그러나 RAID 레벨 5를 사용함으로써 네트웍 오버헤드 문제, 작은 데이터의 기록 성능 문제, 동시 기록 문제가 발생한다. 위의 새 가지 문제를 해결하거나 최소화하기 위하여 본 논문에서는 Parity Cumulating이라는 접근방법을 제시한다. Parity Cumulating은 패리티의 계산을 두 개의 노드로 분산시킴으로써 네트웍 오버헤드를 줄이고, 패리티를 버퍼에 저장하고 디스크에 작업이 없을 때 처리함으로써 작은 데이터의 기록 성능을 높이며 동시 기록시 일관성을 지킨다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.373-376
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• 2002

RAID 저장장치는 병렬성과 고 가용성을 추구하는 대용량 저장장치를 구축하는 방법이다. 특히 패리티 디클러스터링을 사용한 RAID 저장장치는 고장이 발생하였을 경우 재구축 작업중에도 사용자의 요청을 처리함에 있어서 성능 저하가 적고 높은 fault tolerance 와 고 가용성을 지원한다. 본 논문에서는 기존의 패리티 디클러스터링 기법과 분산 스페어링 기법을 적용한 RAID 구조에서 올 수 있는 단점을 보완할 수 있는 새로운 분산 스페어 기법을 제안한다. 본 논문에서 제안된 기법은 시뮬레이션을 통해 그 유효성이 입증되었고, 전반적으로 기존의 방식보다 $1%\sim11%$정도 성능이 더 좋음을 알 수 있다.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.109-114
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• 2024

Enterprise storage systems that require high data reliability are applying RAID (Redundant Array of Independent Disks) systems to recover from data loss and failure. In particular, RAID 5 ensures space efficiency and reliability by distributing parity across multiple storage devices. However, when storage devices have different capacities, RAID is built based on the smallest capacity storage device, resulting in wasted storage space. Therefore, research is needed to solve this resource management problem. In this paper, we propose a method for RAID grouping of each independent NAND flash memory block in a RAID consisting of SSD (Solid State Disk) with external SSDs as well as internal SSDs. This method is divided into a policy for delivering block information inside SSDs to the RAID system and a policy for RAID grouping of physical addresses delivered from the RAID system. This method allows us to maintain a RAID that does not waste resources when SSDs of different capacities are grouped into RAID5. Finally, we demonstrate the effectiveness of the proposed method through experiments.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.12
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• pp.569-576
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• 2013

Cloud computing has been receiving increasing attention recently. Despite this attention, security is the main problem that still needs to be addressed for cloud computing. In general, a cloud computing environment protects data by using distributed servers for data storage. When the amount of data is too high, however, different pieces of a secret key (if used) may be divided among hundreds of distributed servers. Thus, the management of a distributed server may be very difficult simply in terms of its authentication, encryption, and decryption processes, which incur vast overheads. In this paper, we proposed a efficiently data storage and recovery scheme using XOR and RAID in Hadoop environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.644-645
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• 2014

This paper proposes a software defined storaging method to converge the network virtualization techique and the RAID of distributed storage environment. The proposed method designs software based storage which it apply a flexible control and maintenance of storages. In addition, the method overcomes the restricted of physical storage cpapcity and cut cousts of data recovery.