From: John Wilkins Date: Thu, 1 Nov 2012 22:30:39 +0000 (-0700) Subject: doc: Improved the landing page for RBD. X-Git-Tag: v0.55~130^2~24 X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=019fee822418e6b9ec666e0d2bb322d6921c15e4;p=ceph.git doc: Improved the landing page for RBD. Signed-off-by: John Wilkins --- diff --git a/doc/rbd/rbd.rst b/doc/rbd/rbd.rst index e7ec4eb1848f..59c7bde7f030 100644 --- a/doc/rbd/rbd.rst +++ b/doc/rbd/rbd.rst @@ -2,23 +2,36 @@ Block Devices =============== -A block is a sequence of bytes (for example, a 512-byte block of data). -Block-based storage interfaces are the most common way to store data with -rotating media such as hard disks, CDs, floppy disks, and even traditional -9-track tape. The ubiquity of block device interfaces makes a virtual block +A block is a sequence of bytes (for example, a 512-byte block of data). +Block-based storage interfaces are the most common way to store data with +rotating media such as hard disks, CDs, floppy disks, and even traditional +9-track tape. The ubiquity of block device interfaces makes a virtual block device an ideal candidate to interact with a mass data storage system like Ceph. -Ceph's RADOS Block Devices (RBD) interact with OSDs using the -``librados`` and ``librbd`` libraries. RBDs are thin-provisioned, resizable -and store data striped over multiple OSDs in a Ceph cluster. RBDs inherit -``librados`` capabilities such as snapshotting and cloning. Ceph's RBDs deliver -high performance with infinite scalability to kernel objects, kernel virtual -machines and cloud-based computing systems like OpenStack and CloudStack. +Ceph block devices are thin-provisioned, resizable and store data striped over +multiple OSDs in a Ceph cluster. Ceph block devices leverage +:abbr:`RADOS (Reliable Autonomic Distributed Object Store)` capabilities +such as snapshotting, replication and consistency. Ceph's +:abbr:`RADOS (Reliable Autonomic Distributed Object Store)` Block Devices (RBD) +interact with OSDs using kernel modules or the ``librbd`` library. -The ``librbd`` library converts data blocks into objects for storage in -RADOS OSD clusters--the same storage system for ``librados`` object stores and -the Ceph FS filesystem. You can use the same cluster to operate object stores, -the Ceph FS filesystem, and RADOS block devices simultaneously. +.. ditaa:: +------------------------+ +------------------------+ + | Kernel Module | | librbd | + +------------------------+-+------------------------+ + | RADOS Protocol | + +------------------------+-+------------------------+ + | OSDs | | Monitors | + +------------------------+ +------------------------+ + +.. note:: Kernel modules can use Linux page caching. For ``librbd``-based + applications, Ceph supports `RBD Caching`_. + +Ceph's block devices deliver high performance with infinite scalability to +`kernel modules`_, or to :abbr:`KVMs (kernel virtual machines)` such as `Qemu`_, and +cloud-based computing systems like `OpenStack`_ and `CloudStack`_ that rely on +libvirt and Qemu to integrate with Ceph block devices. You can use the same cluster +to operate the `Ceph RADOS Gateway`_, the `Ceph FS filesystem`_, and Ceph block +devices simultaneously. .. important:: To use RBD, you must have a running Ceph cluster. @@ -26,12 +39,18 @@ the Ceph FS filesystem, and RADOS block devices simultaneously. :maxdepth: 1 Commands - Kernel Objects + Kernel Modules Snapshots QEMU libvirt + Cache Settings <../../config-cluster/rbd-config-ref/> OpenStack CloudStack - - - + +.. _RBD Caching: ../../config-cluster/rbd-config-ref/ +.. _kernel modules: ../rbd-ko/ +.. _Qemu: ../qemu-rbd/ +.. _OpenStack: ../rbd-openstack +.. _CloudStack: ../rbd-cloudstack +.. _Ceph RADOS Gateway: ../../radosgw/ +.. _Ceph FS filesystem: ../../cephfs/