Re: [openstack-dev] [cinder] dd performance for wipe in cinder

2013-10-11 Thread John Griffith
On Fri, Oct 11, 2013 at 11:05 AM, Jeremy Stanley wrote: > On 2013-10-11 10:50:33 -0600 (-0600), Chris Friesen wrote: > > Sounds like we could use some kind of layer that will zero out > > blocks on read if they haven't been written by that user. > [...] > > You've mostly just described thin provi

Re: [openstack-dev] [cinder] dd performance for wipe in cinder

2013-10-11 Thread Jeremy Stanley
On 2013-10-11 10:50:33 -0600 (-0600), Chris Friesen wrote: > Sounds like we could use some kind of layer that will zero out > blocks on read if they haven't been written by that user. [...] You've mostly just described thin provisioning... reads to previously unused blocks are returned empty/all-z

Re: [openstack-dev] [cinder] dd performance for wipe in cinder

2013-10-11 Thread Chris Friesen
On 10/11/2013 09:02 AM, John Griffith wrote: As Matt pointed out there's an option to turn off secure-delete altogether. The reason for the volume_clear setting (aka secure delete) is that since we're allocating volumes via LVM from a shared VG there is the possibility that a user had a volume

Re: [openstack-dev] [cinder] dd performance for wipe in cinder

2013-10-11 Thread John Griffith
On Fri, Oct 11, 2013 at 8:41 AM, Matt Riedemann wrote: > Have you looked at the volume_clear and volume_clear_size options in > cinder.conf? > > * > https://github.com/openstack/cinder/blob/2013.2.rc1/etc/cinder/cinder.conf.sample#L1073 > *

Re: [openstack-dev] [cinder] dd performance for wipe in cinder

2013-10-11 Thread Matt Riedemann
Have you looked at the volume_clear and volume_clear_size options in cinder.conf? https://github.com/openstack/cinder/blob/2013.2.rc1/etc/cinder/cinder.conf.sample#L1073 The default is to zero out the volume. You could try 'none' to see if that helps with performance. Thanks, MATT RIEDE