EVENODD Code Research Articles

Storage and Data Processing Technology in the Era of Information Explosion: from Traditional to Edge Computing

Data-intensive IoT gradually occupying the market, and efficient and reliable storage algorithms of signals and information are becoming increasingly important. The old-era storage algorithms no longer meet the needs of digital and intelligent cloud storage due to large space usage and low operating efficiency. One of the important topics in IoT cloud computing is to find a turning point from traditional storage methods to develop data-intensive and efficient storage methods. This research analyzed the principles, features, advantages, and disadvantages of many classic storage algorithms, including RS code, EVENODD code, Pyramid code, etc. It is to find storage algorithms suitable with higher storage efficiency in the IoT. Finally, Pyramid code is leading in data recovery efficiency and scalability and is suitable for higher and faster storage needs of the IoT. However, the shortcoming of Pyramid code also has challenges in the large number of failures that occur, due to its slower recovery speed.

Performance Comparison and Analysis of RAID-6 Encoding and Scaling in Edge Computing Environments

In today's world where cloud computing is widely used, edge computing is starting to be used as a new type of data computing and management service. This paper first describes the importance of data reliability and storage fault tolerance for edge computing operating in multiple environments, and then focuses on RAID-6 to address the data storage requirements of edge computing. In this paper, the feasibility of RAID-6 for edge computing is discussed and two different RAID-6 coding algorithms are introduced. The better option for edge computing is explored through performance comparison. Among the two RAID-6 coding algorithms, it is considered that Row-Diagonal parity will be more suitable than EVENODD code for edge computing scenarios through comparison. But perhaps there are better coding algorithms with lower complexity that can again improve the performance of edge computing storage systems. An edge computing storage system using RAID-6 architecture would be very beneficial for a wide range of real-world application scenarios.

The Advantages and Disadvantages of Codec Between RDP Code and EVENODD Code

With the rapid change of The Times, the number of people and devices continues to grow, and the amount of data begins to explode, which brings great challenges to the current data storage means. In this context, this paper mainly compares the advantages and disadvantages of RDP code and EVENODD code in RAID6 disk array system. This paper first introduces the coding principle and decoding principle of RDP algorithm, and then introduces the coding principle and decoding principle of EVENODD code. Finally, the two algorithms are compared in performance, redundancy data element and coding cost. Compared with EVENODD algorithm, RDP algorithm has obvious advantages in all aspects. Through the analysis of the calculation results, RDP algorithm is significantly better than EVENODD algorithm in terms of data elements to be called, redundant elements and coding calculation cost. This shows that using RDP coding algorithm can reduce system overhead and improve system performance and efficiency. Therefore, RDP codes have a better advantage in RAID6 disk array systems. In summary, this paper compares the advantages and disadvantages of RDP encoding and EVENODD encoding. The calculation results show that the algorithm can significantly increase the amount of data transmission and redundant data while reducing the overhead. This provides an effective guarantee for the reliable operation of RAID6 disk array system. This research has certain guiding significance to improve the performance and reliability of the system.

On the MDS Condition of Blaum–Bruck–Vardy Codes With Large Number Parity Columns

Binary maximum distance separable (MDS) array codes are widely used in storage systems. EVENODD code and row-diagonal parity (RDP) code are two well-known binary MDS array codes with two parity columns. The Blaum–Bruck–Vardy (BBV) code is an extension of the double-erasure-correcting EVENODD code. It is known that the BBV code is always MDS for three parity columns, and sufficient conditions for up to eight parity columns to be MDS are also known. However, the MDS condition for more than eight parity columns is an open problem since then. In this letter, we study the MDS condition of BBV code and give a sufficient MDS condition of the BBV code with more than eight parity columns.

An Efficient MDS Array Code on Toleration Triple Node Failures in Storage System

Proper data placement schemes based on erasure correcting code are one of the most important components for a highly available data storage system. A new class of Maximum Distance Separable (MDS) array codes is presented for correcting triple storage failures, which is an extension of the double-erasure-correcting EVENODD code and is called the HDD-EOD code. The encoding and decoding procedures are described by geometrical line graph, which are easily implemented by soft hardware. Our analysis shows that the HDD-EOD code provides better decoding performance and higher reliability compared to other popular codes. Thus the HDD-EOD code is practically very meaningful for storage systems.

A Hybrid Approach to Failed Disk Recovery Using RAID-6 Codes

The current parallel storage systems use thousands of inexpensive disks to meet the storage requirement of applications. Data redundancy and/or coding are used to enhance data availability, for instance, Row-diagonal parity (RDP) and EVENODD codes, which are widely used in RAID-6 storage systems, provide data availability with up to two disk failures . To reduce the probability of data unavailability, whenever a single disk fails, disk recovery will be carried out. We find that the conventional recovery schemes of RDP and EVENODD codes for a single failed disk only use one parity disk. However, there are two parity disks in the system, and both can be used for single disk failure recovery. In this article, we propose a hybrid recovery approach that uses both parities for single disk failure recovery, and we design efficient recovery schemes for RDP code (RDOR-RDP) and EVENODD code (RDOR-EVENODD). Our recovery scheme has the following attractive properties: (1) “ read optimality ” in the sense that our scheme issues the smallest number of disk reads to recover a single failed disk and it reduces approximately 1/4 of disk reads compared with conventional schemes; (2) “ load balancing property ” in that all surviving disks will be subjected to the same (or almost the same) amount of additional workload in rebuilding the failed disk. We carry out performance evaluation to quantify the merits of RDOR-RDP and RDOR-EVENODD on some widely used disks with DiskSim. The offline experimental results show that RDOR-RDP and RDOR-EVENODD outperform the conventional recovery schemes of RDP and EVENODD codes in terms of total recovery time and recovery workload on individual surviving disk. However, the improvements are less than the theoretical value (approximately 25%), as RDOR-RDP and RDOR-EVENODD change the disk access pattern from purely sequential to a more random one compared with their conventional schemes.

STAR : An Efficient Coding Scheme for Correcting Triple Storage Node Failures

Proper data placement schemes based on erasure correcting codes are one of the most important components for a highly available data storage system. For such schemes, low decoding complexity for correcting (or recovering) storage node failures is essential for practical systems. In this paper, we describe a new coding scheme, which we call the STAR code, for correcting triple storage node failures (erasures). The STAR code is an extension of the double-erasure-correcting EVENODD code and a modification of the generalized triple-erasure-correcting EVENODD code. The STAR code is an Maximum Distance Separable (MDS) code and thus is optimal in terms of node failure recovery capability for a given data redundancy. We provide detailed STAR code decoding algorithms for correcting various triple node failures. We show that the decoding complexity of the STAR code is much lower than those of existing comparable codes; thus, the STAR code is practically very meaningful for storage systems that need higher reliability.

Modified Low-Density MDS Array Codes for Tolerating Double Disk Failures in Disk Arrays

In this paper, we present a new class of low-density MDS array codes for tolerating double disk failures in disk arrays. The proposed MDS array code has lower encoding and decoding complexity than the EVENODD code of Blaum et al

The Burst Error Correcting Capabilities of a Simple Array Code

We propose a simple decoder for a widely used array code, known as the EVENODD code, which is originally designed to correct phased burst errors, to make it useful for correcting nonphased errors. The proposed scheme is capable of correcting almost all bursts up to a certain length. We show that the failure rate is sufficiently small and approaches zero as the block length increases. The redundancy of the code is twice the maximal burst length, which is a lower bound for the redundancy of a true burst-error-correcting code. Both the encoder and the decoder have very low complexity, both in terms of number of operations and in terms of computer code size