openstack/openstack-ansible
Code Issues Proposed changes
00a3ff23c5
openstack-ansible/doc/source/install-guide/configure-swift-policies.rst
kevin f9f907732e Port basic installation guide 
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>
2015-06-11 09:17:56 -05:00

2.1 KiB
Raw Blame History

Home 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