mirror of
https://github.com/ceph/ceph
synced 2024-12-21 19:02:10 +00:00
152f4fba1e
Fixes: https://github.com/ceph/ceph/pull/22784#discussion_r200755460 Signed-off-by: Jos Collin <jcollin@redhat.com>
73 lines
2.6 KiB
ReStructuredText
73 lines
2.6 KiB
ReStructuredText
===================
|
|
Ceph Block Device
|
|
===================
|
|
|
|
.. index:: Ceph Block Device; introduction
|
|
|
|
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 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.
|
|
|
|
.. 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 `CephFS filesystem`_, and Ceph block
|
|
devices simultaneously.
|
|
|
|
.. important:: To use Ceph Block Devices, you must have access to a running
|
|
Ceph cluster.
|
|
|
|
.. toctree::
|
|
:maxdepth: 1
|
|
|
|
Commands <rados-rbd-cmds>
|
|
Kernel Modules <rbd-ko>
|
|
Snapshots<rbd-snapshot>
|
|
Mirroring <rbd-mirroring>
|
|
LIO iSCSI Gateway <iscsi-overview>
|
|
QEMU <qemu-rbd>
|
|
libvirt <libvirt>
|
|
Cache Settings <rbd-config-ref/>
|
|
OpenStack <rbd-openstack>
|
|
CloudStack <rbd-cloudstack>
|
|
RBD Replay <rbd-replay>
|
|
|
|
.. 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
|
|
.. _Ceph RADOS Gateway: ../../radosgw/
|
|
.. _CephFS filesystem: ../../cephfs/
|