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

John Griffith john.griffith at solidfire.com
Fri Oct 11 15:02:31 UTC 2013


On Fri, Oct 11, 2013 at 8:41 AM, Matt Riedemann <mriedem at us.ibm.com> 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
> *<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 RIEDEMANN*
> Advisory Software Engineer
> Cloud Solutions and OpenStack Development
> ------------------------------
>  *Phone:* 1-507-253-7622 | *Mobile:* 1-507-990-1889*
> E-mail:* *mriedem at us.ibm.com* <mriedem at us.ibm.com>
> [image: IBM]
>
> 3605 Hwy 52 N
> Rochester, MN 55901-1407
> United States
>
>
>
>
>
> From:        cosmos cosmos <cosmos0703 at gmail.com>
> To:        openstack-dev at lists.openstack.org,
> Date:        10/11/2013 04:26 AM
> Subject:        [openstack-dev]  dd performance for wipe in cinder
> ------------------------------
>
>
>
> Hello.
> My name is Rucia for Samsung SDS.
>
> Now I am in trouble in cinder volume deleting.
> I am developing for supporting big data storage in lvm
>
> But it takes too much time for deleting of cinder lvm volume because of dd.
> Cinder volume is 200GB for supporting hadoop master data.
> When i delete cinder volume in using 'dd if=/dev/zero of $cinder-volume
> count=1000000 bs=1M' it takes about 30 minutes.
>
> Is there the better and quickly way for deleting?
>
> Cheers.
> Rucia.
>
>
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>
> 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 with sensitive data and
deleted/removed the logical volume they were using.  If there was no
encryption or if no secure delete operation were performed it is possible
that another tenant when creating a new volume from the Volume Group could
be allocated some of the blocks that the previous volume utilized and
potentially inspect/read those blocks and obtain some of the other users
data.

To be honest the options provided won't likely make this operation as
"fast" as you'd like, especially when dealing with 200GB volumes.
 Depending on your environment you may want to consider using encryption or
possibly if acceptable using the volume_clear=None.

John
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