<div dir="ltr"><div class="gmail_default" style="font-family:courier new,monospace"><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Oct 11, 2013 at 8:41 AM, Matt Riedemann <span dir="ltr"><<a href="mailto:mriedem@us.ibm.com" target="_blank">mriedem@us.ibm.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><font face="sans-serif">Have you looked at the volume_clear and
volume_clear_size options in cinder.conf?</font>
<br>
<br><a href="https://github.com/openstack/cinder/blob/2013.2.rc1/etc/cinder/cinder.conf.sample#L1073" target="_blank"><font size="3" color="blue"><u>https://github.com/openstack/cinder/blob/2013.2.rc1/etc/cinder/cinder.conf.sample#L1073</u></font></a><font size="3">
</font>
<br>
<br><font face="sans-serif">The default is to zero out the volume.
You could try 'none' to see if that helps with performance.<br>
</font>
<br><font face="sans-serif"><br>
</font>
<br><font size="1" face="Arial">Thanks,</font>
<br>
<br><font size="3" color="#8f8f8f" face="Arial"><b>MATT RIEDEMANN</b></font><font size="1" face="Arial"><br>
Advisory Software Engineer<br>
Cloud Solutions and OpenStack Development</font>
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<br>
<br><font size="1" color="#5f5f5f" face="sans-serif">From:
</font><font size="1" face="sans-serif">cosmos cosmos <<a href="mailto:cosmos0703@gmail.com" target="_blank">cosmos0703@gmail.com</a>></font>
<br><font size="1" color="#5f5f5f" face="sans-serif">To:
</font><font size="1" face="sans-serif"><a href="mailto:openstack-dev@lists.openstack.org" target="_blank">openstack-dev@lists.openstack.org</a>,
</font>
<br><font size="1" color="#5f5f5f" face="sans-serif">Date:
</font><font size="1" face="sans-serif">10/11/2013 04:26 AM</font>
<br><font size="1" color="#5f5f5f" face="sans-serif">Subject:
</font><font size="1" face="sans-serif">[openstack-dev]
dd performance for wipe in cinder</font>
<br>
<hr noshade><div class="HOEnZb"><div class="h5">
<br>
<br>
<br><font size="3">Hello.</font>
<br><font size="1" face="Arial">My name is Rucia for Samsung SDS.</font>
<br>
<br><font size="1" face="Arial">Now I am in trouble in cinder volume deleting.</font>
<br><font size="1" face="Arial">I am developing for supporting big data storage
in lvm </font>
<br>
<br><font size="1" face="Arial">But it takes too much time for deleting of
cinder lvm volume because of dd.</font>
<br><font size="1" face="Arial">Cinder volume is 200GB for supporting hadoop
master data.</font>
<br><font size="1" face="Arial">When i delete cinder volume in using 'dd
if=/dev/zero of $cinder-volume count=1000000 bs=1M' it takes about 30 minutes.</font>
<br>
<br><font size="1" face="Arial">Is there the better and quickly way for deleting?</font>
<br>
<br><font size="1" face="Arial">Cheers. </font>
<br><font size="1" face="Arial">Rucia.</font>
<br>
<br>
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<br></blockquote></div><div class="gmail_default" style="font-family:'courier new',monospace">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.</div>
<div class="gmail_default" style="font-family:'courier new',monospace"><br></div><div class="gmail_default" style="font-family:'courier new',monospace">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.</div>
<div class="gmail_default" style="font-family:'courier new',monospace"><br></div><div class="gmail_default" style="font-family:'courier new',monospace">John</div></div></div>