f9f907732e
Convert RPC installation guide from DocBook to RST, remove content specific to Rackspace, and create initial OSAD installation guide. Change-Id: I3eedadc8ba441b4d931720dd6e3f7f3489302a9c Co-Authored-By: Matt Kassawara <mkassawara@gmail.com>
53 lines
2.1 KiB
ReStructuredText
53 lines
2.1 KiB
ReStructuredText
`Home <index.html>`__ OpenStack Ansible Installation Guide
|
|
|
|
Storage Policies
|
|
----------------
|
|
|
|
Storage Policies allow segmenting the cluster for various purposes
|
|
through the creation of multiple object rings. Using policies, different
|
|
devices can belong to different rings with varying levels of
|
|
replication. By supporting multiple object rings, Object Storage can
|
|
segregate the objects within a single cluster.
|
|
|
|
Storage policies can be used for the following situations:
|
|
|
|
- Differing levels of replication: A provider may want to offer 2x
|
|
replication and 3x replication, but does not want to maintain two
|
|
separate clusters. They can set up a 2x policy and a 3x policy and
|
|
assign the nodes to their respective rings.
|
|
|
|
- Improving performance: Just as solid state drives (SSD) can be used
|
|
as the exclusive members of an account or database ring, an SSD-only
|
|
object ring can be created to implement a low-latency or high
|
|
performance policy.
|
|
|
|
- Collecting nodes into groups: Different object rings can have
|
|
different physical servers so that objects in specific storage
|
|
policies are always placed in a specific data center or geography.
|
|
|
|
- Differing storage implementations: A policy can be used to direct
|
|
traffic to collected nodes that use a different disk file (for
|
|
example, Kinetic, GlusterFS).
|
|
|
|
Most storage clusters do not require more than one storage policy. The
|
|
following problems can occur if using multiple storage policies per
|
|
cluster:
|
|
|
|
- Creating a second storage policy without any specified drives (all
|
|
drives are part of only the account, container, and default storage
|
|
policy groups) creates an empty ring for that storage policy.
|
|
|
|
- A non-default storage policy is used only if specified when creating
|
|
a container, using the
|
|
``X-Storage-Policy: <policy-name>`` header. After the
|
|
container is created, it uses the created storage policy. Other
|
|
containers continue using the default or another storage policy
|
|
specified when created.
|
|
|
|
For more information about storage policies, see: `Storage
|
|
Policies <http://docs.openstack.org/developer/swift/overview_policies.html>`__
|
|
|
|
--------------
|
|
|
|
.. include:: navigation.txt
|