In an object-based storage system,a novel scheme named EAP(extending attributes page) is presented to enhance the metadata reliability of the system by adding the user object file information attributes page for each user object and storing the file-related attributes of each user object in object-based storage devices.The EAP scheme requires no additional hardware equipments compared to a general method which uses backup metadata servers to improve the metadata reliability.Leveraging a Markov chain,this paper compares the metadata reliability of the system using the EAP scheme with that using only metadata servers to offer the file metadata service.Our results demonstrate that the EAP scheme can dramatically enhance the reliability of storage system metadata.
在基于可扩展对象的海量存储系统(Based on Scalable Object Mass Storage System,BSO-MSS)中,负载均衡一直是研究的重点,如何选择存储对象(Storage Object,SO)及数目是关键。因此提出柔性负载均衡策略,它不仅考虑网络对BSO-MSS的影响,而且更关注SO本身,针对SO中不同的存储能力,自适应选择SO数目,采用不同大小的分条进行存储。当SO数目未达到最佳值时,增加SO数目,会减少系统响应时间,提高整个系统的吞吐量。
Apart from high space efficiency,other demanding requirements for enterprise de-duplication backup are high performance,high scalability,and availability for large-scale distributed environments.The main challenge is reducing the significant disk input/output(I/O) overhead as a result of constantly accessing the disk to identify duplicate chunks.Existing inline de-duplication approaches mainly rely on duplicate locality to avoid disk bottleneck,thus suffering from degradation under poor duplicate locality workload.This paper presents Chunkfarm,a post-processing de-duplication backup system designed to improve capacity,throughput,and scalability for de-duplication.Chunkfarm performs de-duplication backup using the hash join algorithm,which turns the notoriously random and small disk I/Os of fingerprint lookups and updates into large sequential disk I/Os,hence achieving high write throughput not influenced by workload locality.More importantly,by decentralizing fingerprint lookup and update,Chunkfarm supports a cluster of servers to perform de-duplication backup in parallel;it hence is conducive to distributed implementation and thus applicable to large-scale and distributed storage systems.
Tian-ming YANG Dan FENG Zhong-ying NIU Ya-ping WAN
