Support setting block size for block devices

[OpenStack Infra]

https://review.openstack.org/35214
commit 1549f33442f7eb861fffb67987de2d8f2e397327
Author: Chet Burgess <email address hidden>
Date: Fri Jun 28 21:21:36 2013 +0000

    Support setting block size for block devives

    cinder now supports backend with different block sizes. Sometimes
    we need to set a specific block size or operations against the
    backend will result in I/O errors. Additionally its a good idea
    to tune the block sizes to the correct size as it can improve I/O
    performance.

    The basic disk configuration for libvrit now supports setting the
    logical and physical block size of devices. We pull the block size
    from the volume metadata and store it in the connection_info of
    the block_device_mapping table for later use.

    By default it does not set the block sizes which defaults to
    512 bytes.

    DocImpact:
    This feature requires libvirt 0.10.2+ and the QEMU or KVM
    hpypervisor. If a volume has a custom block size, the hypervisor
    and libvirt version are checked during the attach_volume call. If
    the hypervisor is not supported or the libvirt version is too old
    the attach is aborted and an exception is raised.

    Change-Id: I77adc96b340680218f82bbef8f9ec14711d26a7f
    Fixes Bug #1195913

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/48112

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/48112
Committed: http://github.com/openstack/openstack-manuals/commit/610f4a88c8a5e1c5a6113e9dd86f3d4f4f6addeb
Submitter: Jenkins
Branch: master

commit 610f4a88c8a5e1c5a6113e9dd86f3d4f4f6addeb
Author: annegentle <email address hidden>
Date: Tue Sep 24 13:13:20 2013 -0500

    Adds note about block size settings to accomodate custom block sizes

    Change-Id: I6bc4c09066855d82bd5f17ba40ce1909b7443c99
    Closes-bug: 1197449