mirror of
https://github.com/ceph/ceph
synced 2024-12-27 22:13:28 +00:00
73 lines
2.3 KiB
ReStructuredText
73 lines
2.3 KiB
ReStructuredText
===================
|
|
Ceph Block Device
|
|
===================
|
|
|
|
.. index:: Ceph Block Device; introduction
|
|
|
|
A block is a sequence of bytes (often 512).
|
|
Block-based storage interfaces are a mature and common way to store data on
|
|
media including HDDs, SSDs, CDs, floppy disks, and even tape.
|
|
The ubiquity of block device interfaces is a perfect fit for interacting
|
|
with mass data storage including Ceph.
|
|
|
|
Ceph block devices are thin-provisioned, resizable, and store data striped over
|
|
multiple OSDs. Ceph block devices leverage
|
|
:abbr:`RADOS (Reliable Autonomic Distributed Object Store)` capabilities
|
|
including snapshotting, replication and strong consistency. Ceph block
|
|
storage clients communicate with Ceph clusters through kernel modules or
|
|
the ``librbd`` library.
|
|
|
|
.. 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 vast 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 :ref:`Ceph RADOS Gateway <object-gateway>`, the
|
|
:ref:`Ceph File System <ceph-file-system>`, and Ceph block devices simultaneously.
|
|
|
|
.. important:: To use Ceph Block Devices, you must have access to a running
|
|
Ceph cluster.
|
|
|
|
.. toctree::
|
|
:maxdepth: 1
|
|
|
|
Basic Commands <rados-rbd-cmds>
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
Operations <rbd-operations>
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
Integrations <rbd-integrations>
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
Manpages <man/index>
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
APIs <api/index>
|
|
|
|
.. _RBD Caching: ./rbd-config-ref/
|
|
.. _kernel modules: ./rbd-ko/
|
|
.. _QEMU: ./qemu-rbd/
|
|
.. _OpenStack: ./rbd-openstack
|
|
.. _CloudStack: ./rbd-cloudstack
|