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In computing, Ceph is a free software storage platform that stores data on a single distributed computer cluster, and provides interfaces for object-, block- and file-level storage. Ceph aims primarily to be completely distributed without a single point of failure, scalable to the exabyte level, and freely available. Ceph replicates data and makes it fault-tolerant, using commodity hardware and requiring no specific hardware support. As a result of its design, the system is both self-healing and self-managing, aiming to minimize administration time and other costs. ==Design== Ceph employs four distinct kinds of daemons: * Cluster monitors () that keep track of active and failed cluster nodes * Metadata servers () that store the metadata of inodes and directories * Object storage devices () that actually store the content of files. Ideally, OSDs store their data on a local btrfs filesystem to leverage its built-in copy-on-write capabilities, though other local filesystems can be used instead.〔(【引用サイトリンク】title=Btrfs - Ceph Wiki )〕 * Representational state transfer (RESTful) gateways () that expose the object storage layer as an interface compatible with Amazon S3 or OpenStack Swift APIs All of these are fully distributed, and may run on the same set of servers. Clients directly interact with all of them. Ceph does striping of individual files across multiple nodes to achieve higher throughput, similarly to how RAID0 stripes partitions across multiple hard drives. Adaptive load balancing is supported whereby frequently accessed objects are replicated over more nodes. , underlying filesystems recommended for production environments are ext4 (small scale) and XFS (large scale deployments), while Btrfs and ZFS are recommended for non-production environments.〔(【引用サイトリンク】url=http://ceph.com/docs/master/rados/configuration/filesystem-recommendations/ )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ceph (software)」の詳細全文を読む スポンサード リンク
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