Block size for dd command in LVM driver not configurable

[Christoph Kassen]

The block size used by the dd command in the LVM driver is currently set to 1M. In our setup this leads to poor performance, especially when deleting volumes.

By setting the block sized passed to dd to a higher value we could improve the performance. Unfortunately the block size used is not user configurable.

I'm working on a patch which adds an additional configuration option making the bs parameter passed to dd user configurable.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/24833

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/24833
Committed: http://github.com/openstack/cinder/commit/8e8f200d909ff62c9286d585e658dab93bdfea67
Submitter: Jenkins
Branch: master

commit 8e8f200d909ff62c9286d585e658dab93bdfea67
Author: Christoph Kassen <email address hidden>
Date: Tue Mar 19 21:50:51 2013 +0100

    Make dd block size user configurable

    This patch introduces a new configuration option volume_dd_blocksize
    to change the bs parameter passed to the dd command when creating or
    deleting volumes. In certain scenarios changing the block size might
    result in better performance.

    The default value is still 1M, which was used before.

    Change-Id: I0398436ab3ecca51f6121e8f521af8b2dc60acd3
    Fixes: bug #1157417