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Bug 1535529

Summary:	Use dd conv=sparse when writing images to nodes
Product:	Red Hat OpenStack	Reporter:	Ian Pilcher <ipilcher>
Component:	python-ironic-lib	Assignee:	Ian Pilcher <ipilcher>
Status:	CLOSED ERRATA	QA Contact:	mlammon
Severity:	medium	Docs Contact:
Priority:	medium
Version:	12.0 (Pike)	CC:	apevec, bfournie, ipilcher, jjoyce, jschluet, lhh, racedoro
Target Milestone:	z3	Keywords:	Triaged, ZStream
Target Release:	12.0 (Pike)
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	python-ironic-lib-2.10.1-1.el7ost	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-08-20 12:46:38 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Ian Pilcher 2018-01-17 15:04:44 UTC

When using whole disk images, one generally wants the *virtual* size of the image to be close to the size of the overcloud nodes' physical disks (since no partition/logical volume/filesystem) expansion is done). As an example, one might end up with a 4GB overcloud image (QCOW file) that has a virtual size of 100GB or more.

Ironic uses qemu-img to convert this QCOW file to a "raw" image, which is a *sparse* file. When the image is copied to an overcloud node's disk (via iSCSI), we currently write all 100GB (mainly of zeroes) across the network to the node's disk.

Adding conv=sparse to the dd command makes it skip the "holes" in the image file; it will only the write the portions of the image that actually contain data across the network.

Comment 2 mlammon 2018-07-18 16:43:32 UTC

Install latest osp12 puddle 

Environment:
python-ironic-lib-2.10.1-1.el7ost.noarch

I can verify the code has landed. 
sed -n '293,294p' /usr/lib/python2.7/site-packages/ironic_lib/disk_utils.py
    utils.dd(src, dst, 'bs=%s' % CONF.disk_utils.dd_block_size, 'oflag=direct',
             'conv=sparse')

Please re-open bug if issue persists.

Comment 5 errata-xmlrpc 2018-08-20 12:46:38 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:2517

Comment 6 Bob Fournier 2018-09-13 16:09:21 UTC

This change appears to have caused a problem booting whole disk images, see https://bugzilla.redhat.com/show_bug.cgi?id=1618548

Comment 7 Red Hat Bugzilla 2023-09-14 04:15:36 UTC

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days