7 research outputs found
On the I/O Costs of Some Repair Schemes for Full-Length Reed-Solomon Codes
Network transfer and disk read are the most time consuming operations in the
repair process for node failures in erasure-code-based distributed storage
systems. Recent developments on Reed-Solomon codes, the most widely used
erasure codes in practical storage systems, have shown that efficient repair
schemes specifically tailored to these codes can significantly reduce the
network bandwidth spent to recover single failures. However, the I/O cost, that
is, the number of disk reads performed in these repair schemes remains largely
unknown. We take the first step to address this gap in the literature by
investigating the I/O costs of some existing repair schemes for full-length
Reed-Solomon codes.Comment: Accepted by the ISIT'1
Network Traffic Driven Storage Repair
Recently we constructed an explicit family of locally repairable and locally
regenerating codes. Their existence was proven by Kamath et al. but no explicit
construction was given. Our design is based on HashTag codes that can have
different sub-packetization levels. In this work we emphasize the importance of
having two ways to repair a node: repair only with local parity nodes or repair
with both local and global parity nodes. We say that the repair strategy is
network traffic driven since it is in connection with the concrete system and
code parameters: the repair bandwidth of the code, the number of I/O
operations, the access time for the contacted parts and the size of the stored
file. We show the benefits of having repair duality in one practical example
implemented in Hadoop. We also give algorithms for efficient repair of the
global parity nodes.Comment: arXiv admin note: text overlap with arXiv:1701.0666