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119 lines
4.1 KiB
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=====================
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Ceph Product Overview
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=====================
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About this Document
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===================
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This document describes the features and benefits of using the Ceph
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Unified Distributed Storage System, and why it is superior to other
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systems.
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The audience for this document consists of sales and marketing
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personnel, new customers, and all persons who need to get a basic
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overview of the features and functionality of the system.
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Introduction to Ceph
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====================
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Ceph is a unified, distributed file system that operates on a large
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number of hosts connected by a network. Ceph has been designed to
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accommodate multiple petabytes of storage with ease. Since file sizes
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and network systems are always increasing, Ceph is perfectly
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positioned to accommodate these new technologies with its unique,
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self-healing and self-replicating architecture. Customers that need
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to move large amounts of metadata, such as media and entertainment
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companies, can greatly benefit from this product. Ceph is also
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dynamic; no need to cache data like those old-fashioned
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client-servers!
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Benefits of Using Ceph
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======================
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Ceph's flexible and scalable architecture translates into cost savings
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for users. Its powerful load balancing technology ensures the highest
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performance in terms of both speed and reliability. Nodes can be
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added "on the fly" with no impact to the system. In the case of node
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failure, the load is re-distributed with no degradation to the system.
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Failure detection is rapid and immediately remedied by efficiently
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re-adding nodes that were temporarily cut off from the network.
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Manageability
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=============
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Ceph is easy to manage, requiring little or no system administrative
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intervention. Its powerful placement algorithm and intelligent nodes
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manage data seamlessly across any node configuration. It also
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features multiple access methods to its object storage, block storage,
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and file systems. Figure 1 displays this configuration.
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.. image:: /images/CEPHConfig.jpg
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RADOS
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=====
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The Reliable Autonomic Distributed Object Store (RADOS) provides a
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scalable object storage management platform. RADOS allows the Object
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Storage Devices (OSD) to operate autonomously when recovering from
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failures or migrating data to expand clusters. RADOS employs existing
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node device intelligence to maximized scalability.
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The RADOS Block Device (RBD) provides a block device interface to a
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Linux machine, while striping the data across multiple RADOS objects
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for improved performance. RDB is supported for Linux kernels 2.6.37
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and higher. Each RDB device contains a directory with files and
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information
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RADOS GATEWAY
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=============
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``radosgw`` is an S3-compatible RESTful HTTP service for object
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storage, using RADOS storage.
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The RADOS Block Device (RBD) provides a block device interface to a
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Linux machine. To the user, RDB is transparent, which means that the
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entire Ceph system looks like a single, limitless hard drive that is
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always up and has no size limitations. .
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Hypervisor Support
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==================
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RBD supports the QEMU processor emulator and the Kernel-based Virtual
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Machine (KVM) virtualization infrastructure for the Linux kernel.
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Normally, these hypervisors would not be used together in a single
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configuration.
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KVM RBD
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-------
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The Linux Kernel-based Virtual Machine (KVM) RBD provides the
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functionality for striping data across multiple distributed RADOS
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objects for improved performance.
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KVM-RDB is supported for Linux kernels 2.6.37 and higher. Each RDB
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device contains a directory with files and information.
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KVM employs the XEN hypervisor to manage its virtual machines.
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QEMU RBD
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--------
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QEMU-RBD facilitates striping a VM block device over objects stored in
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the Ceph distributed object store. This provides shared block storage
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to facilitate VM migration between hosts.
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QEMU has its own hypervisor which interfaces with the librdb
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user-space library to store its virtual machines
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Monitors
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========
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Once you have determined your configuration needs, make sure you have
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access to the following documents:
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- Ceph Installation and Configuration Guide
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- Ceph System Administration Guide
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- Ceph Troubleshooting Manual
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