From dd784ae0ea91df29a60d0b14ddc92bb6d1d01e2f Mon Sep 17 00:00:00 2001 From: Joseph Robinson Date: Thu, 3 Sep 2015 14:56:16 +1000 Subject: [PATCH] Support for Cinder volume replication Documenting information on how cloud administrators can adjust the cinder volume driver to enable volume replication. This feature safeguards environments from data loss. Change-Id: I7ba72a14914cb1b0359e532e619ea36dfe1b73e0 Closes-Bug:#1360768 --- .../source/blockstorage_over_subscription.rst | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/doc/admin-guide-cloud/source/blockstorage_over_subscription.rst b/doc/admin-guide-cloud/source/blockstorage_over_subscription.rst index 7b84e048e1..f6ffc6a0f6 100644 --- a/doc/admin-guide-cloud/source/blockstorage_over_subscription.rst +++ b/doc/admin-guide-cloud/source/blockstorage_over_subscription.rst @@ -97,6 +97,38 @@ The above extra specs are used by the scheduler to find a back end that supports thin provisioning, thick provisioning, or both to match the needs of a specific volume type. +Volume replication extra specs +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +OpenStack Block Storage has the ability to create volume replicas. +Cloud administrators can define a storage policy that includes +replication by adjusting the cinder volume driver. Volume replication +for OpenStack Block Storage helps safeguard OpenStack environments from +data loss during disaster recovery. + +To enable replication when creating volume types, configure the cinder +volume with ``capabilities:replication=" True"``. + +Each volume created with the replication capability set to `True` +generates a copy of the volume on a storage back end. + +One use case for replication involves an OpenStack cloud environment +installed accross two data centers located nearby each other. The +distance between the two data centers in this use case is the length of +a city. + +At each data center, a cinder host supports the Block Storage service. +Both data centers include storage back ends. + +Depending on the storage requirements, there can be one or two cinder +hosts. The cloud administrator accesses the +:file:`/etc/cinder/cinder.conf` configuration file and sets +``capabilities:replication=" True"``. + +If one data center experiences a service failure, cloud administrators +can redeploy the VM. The VM will run using a replicated, backed up +volume on a host in the second data center. + Capacity filter ~~~~~~~~~~~~~~~