在对HDFS进行分析和研究的基础上,在HDFS文件分布式系统中应用File System API进行文件存储和访问,并通过改进的蚁群算法对副本选择进行优化。HDFS API能够有效完成海量数据的存储和管理,提高海量数据存储的效率。通过改进的蚁群算法提...在对HDFS进行分析和研究的基础上,在HDFS文件分布式系统中应用File System API进行文件存储和访问,并通过改进的蚁群算法对副本选择进行优化。HDFS API能够有效完成海量数据的存储和管理,提高海量数据存储的效率。通过改进的蚁群算法提升了文件读取时副本选择的效率,进一步提高了系统效率并使负载均衡。展开更多
Real-time encryption and decryption of digital images stored on end-user devices is a challenging task due to the inherent features of the images. Traditional software encryption applications generally suffered from t...Real-time encryption and decryption of digital images stored on end-user devices is a challenging task due to the inherent features of the images. Traditional software encryption applications generally suffered from the expense of user con- venience, performance efficiency, and the level of security provided. To overcome these limitations, the concept of transparent encryption has been proposed. This type of encryption mechanism can be implemented most efficiently with kernel file systems. However, this approach has some disadvantages since developing a new file system and attaching it in the kernel level requires a deep understanding of the kernel internal data structure. A filesystem in userspace （FUSE） can be used to bridge the gap. Never- theless, ctwrent implementations of cryptographic FUSE-based file systems suffered from several weaknesses that make them less than ideal for deployment. This paper describes the design and implementation of ImgFS, a fully transparent cryptographic file system that resides on user space. ImgFS can provide a sophisticated way to access, manage, and monitor all encryption and key management operations for image files stored on the local disk without any interaction from the user. The development of ImgFS has managed to solve weaknesses that have been identified on cryptographic FUSE-based implementations. Experiments were carried out to measure the performance of ImgFS over image files＇ read and write against the cryptographic service, and the results indicated that while ImgFS has managed to provide higher level of security and transparency, its performance was competitive with other established cryptographic FUSE-based schemes of high performance.展开更多
针对目前网络数据量急剧增加所带来的传输性能压力、文件系统开发因内核紧密耦合而导致的困难,以及传统网络文件系统难以适配新型存储介质的问题,提出一种基于扩展用户态文件系统(Extended Filesystem in Userspace,ExtFUSE)的网络文件...针对目前网络数据量急剧增加所带来的传输性能压力、文件系统开发因内核紧密耦合而导致的困难,以及传统网络文件系统难以适配新型存储介质的问题,提出一种基于扩展用户态文件系统(Extended Filesystem in Userspace,ExtFUSE)的网络文件系统(Network File System,NFS)。该系统通过扩展伯克利数据包过滤器实现整体的网络元数据提取、缓存以及预处理功能,以减少数据进出内核空间时因用户-内核模式切换、上下文切换及内存拷贝所致的时间开销,并提升数据访问时的缓存命中率。将该系统部署于MinIO服务器,并将其与用户空间文件系统(Filesystem in Userspace,FUSE)、基于FUSE的Gluster存储架构(Gluster Storage Architecture with Filesystem in Userspace,Gluster-FUSE)之间的性能数据进行对比分析,以此评估所提系统的性能。实验结果表明,所提系统在元数据操作时间上较FUSE平均降低17.3%,较Gluster-FUSE降低12.1%;扩展数据获取操作耗时显著降低,缓存命中率达到92.19%,较FUSE提升4.5%,较Gluster-FUSE提升1.4%,验证了系统在提升网络数据传输效率和稳定性方面的有效性。展开更多
文摘在对HDFS进行分析和研究的基础上,在HDFS文件分布式系统中应用File System API进行文件存储和访问,并通过改进的蚁群算法对副本选择进行优化。HDFS API能够有效完成海量数据的存储和管理,提高海量数据存储的效率。通过改进的蚁群算法提升了文件读取时副本选择的效率,进一步提高了系统效率并使负载均衡。
基金Project partly supported by the Ministry of Higher Education of Malaysia under Grant LRGS/TD/2011/UKM/ICT/02
文摘Real-time encryption and decryption of digital images stored on end-user devices is a challenging task due to the inherent features of the images. Traditional software encryption applications generally suffered from the expense of user con- venience, performance efficiency, and the level of security provided. To overcome these limitations, the concept of transparent encryption has been proposed. This type of encryption mechanism can be implemented most efficiently with kernel file systems. However, this approach has some disadvantages since developing a new file system and attaching it in the kernel level requires a deep understanding of the kernel internal data structure. A filesystem in userspace （FUSE） can be used to bridge the gap. Never- theless, ctwrent implementations of cryptographic FUSE-based file systems suffered from several weaknesses that make them less than ideal for deployment. This paper describes the design and implementation of ImgFS, a fully transparent cryptographic file system that resides on user space. ImgFS can provide a sophisticated way to access, manage, and monitor all encryption and key management operations for image files stored on the local disk without any interaction from the user. The development of ImgFS has managed to solve weaknesses that have been identified on cryptographic FUSE-based implementations. Experiments were carried out to measure the performance of ImgFS over image files＇ read and write against the cryptographic service, and the results indicated that while ImgFS has managed to provide higher level of security and transparency, its performance was competitive with other established cryptographic FUSE-based schemes of high performance.
文摘针对目前网络数据量急剧增加所带来的传输性能压力、文件系统开发因内核紧密耦合而导致的困难,以及传统网络文件系统难以适配新型存储介质的问题,提出一种基于扩展用户态文件系统(Extended Filesystem in Userspace,ExtFUSE)的网络文件系统(Network File System,NFS)。该系统通过扩展伯克利数据包过滤器实现整体的网络元数据提取、缓存以及预处理功能,以减少数据进出内核空间时因用户-内核模式切换、上下文切换及内存拷贝所致的时间开销,并提升数据访问时的缓存命中率。将该系统部署于MinIO服务器,并将其与用户空间文件系统(Filesystem in Userspace,FUSE)、基于FUSE的Gluster存储架构(Gluster Storage Architecture with Filesystem in Userspace,Gluster-FUSE)之间的性能数据进行对比分析,以此评估所提系统的性能。实验结果表明,所提系统在元数据操作时间上较FUSE平均降低17.3%,较Gluster-FUSE降低12.1%;扩展数据获取操作耗时显著降低,缓存命中率达到92.19%,较FUSE提升4.5%,较Gluster-FUSE提升1.4%,验证了系统在提升网络数据传输效率和稳定性方面的有效性。
