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Bug 1450908 - useless warning displays when clone a guest using a real disk partition as backend storage
Summary: useless warning displays when clone a guest using a real disk partition as ba...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: virt-manager
Version: 7.4
Hardware: x86_64
OS: Unspecified
unspecified
medium
Target Milestone: rc
: ---
Assignee: Pavel Hrdina
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-05-15 11:45 UTC by zhoujunqin
Modified: 2018-04-10 11:42 UTC (History)
6 users (show)

Fixed In Version: virt-manager-1.4.3-2.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-04-10 11:40:46 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
Screenshot for guest 'sdc1' (54.00 KB, image/png)
2017-11-27 04:25 UTC, zhoujunqin 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHEA-2018:0726 0 None None None 2018-04-10 11:42:12 UTC

Description zhoujunqin 2017-05-15 11:45:27 UTC 
Description of problem:
useless warning displays when clone a guest using a real disk partition as backend storage

Version-Release number of selected component (if applicable):
virt-manager-1.4.1-3.el7.noarch
virt-install-1.4.1-3.el7.noarch
libvirt-3.2.0-4.el7.x86_64
qemu-kvm-rhev-2.9.0-3.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Prepare a health disk with disk:
# virsh dumpxml import
...
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/sgiotest.img'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
...

# qemu-img info /var/lib/libvirt/images/sgiotest.img
image: /var/lib/libvirt/images/sgiotest.img
file format: raw
virtual size: 6.0G (6442450944 bytes)
disk size: 4.4G

2. Then clone a guest using a real disk partition as backend storage.
# qemu-img info /dev/sdb2
image: /dev/sdb2
file format: raw
virtual size: 20G (21474836480 bytes)
disk size: 0

# virt-clone -o import -n import-clone --file=/dev/sdb2 --check all=off
WARNING  This will overwrite the existing path '/dev/sdb2'
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 6144 M requested > 3866 M available
Cloning sgiotest.img                                                                            | 6.0 GB  00:02:17    

Clone 'import-clone' created successfully.


Actual results:
As description, useless warning displays during cloning.
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 6144 M requested > 3866 M available

Expected results:
Fix it.

Additional info:
Comment 2 Pavel Hrdina 2017-10-03 15:13:14 UTC 
Upstream patch posted:

https://www.redhat.com/archives/virt-tools-list/2017-October/msg00012.html
Comment 3 Pavel Hrdina 2017-10-19 07:24:57 UTC 
Upstream commit:

commit 6e6f59e7abfd85b2a53554b7d091e553585e85c8
Author: Pavel Hrdina <phrdina>
Date:   Tue Oct 3 16:59:13 2017 +0200

    diskbackend: get a proper size of existing block device while cloning
Comment 6 zhoujunqin 2017-11-27 04:23:32 UTC 
Try to verify this bug with new build:
virt-manager-1.4.3-2.el7.noarch
virt-install-1.4.3-2.el7.noarch

1. Prepare a health shutoff guest. 
...
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/rhel7.4-clone.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
...

Then check disk size.

# qemu-img info /var/lib/libvirt/images/rhel7.4-clone.qcow2 
image: /var/lib/libvirt/images/rhel7.4-clone.qcow2
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 3.9G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

2. Clone a guest using a real disk partition as backend storage.

scenairo-1 full_block_disk_size < 9G

# qemu-img info /dev/sdb
image: /dev/sdb
file format: raw
virtual size: 7.5G (8006926336 bytes)
disk size: 0


# virt-clone -o rhel7.4 -n 9-clone --file=/dev/sdb --check all=off
WARNING  This will overwrite the existing path '/dev/disk/by-path/pci-0000:00:1d.0-usb-0:1.3:1.0-scsi-0:0:0:0'
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 9216 M requested > 7636 M available
Cloning rhel7.4-clone.qcow2                                                                                          | 9.0 GB  00:03:39     

Clone '9-clone' created successfully.

# qemu-img info /dev/sdb
image: /dev/sdb
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false


Result:
i. Cloning begins with calculated size '9216 M requested > 7636 M' in warning, it is as expected.
ii. New guest can boot up.


Scenario-2: full_block_disk_size > 9G 

# qemu-img info /dev/sdc
image: /dev/sdc
file format: raw
virtual size: 29G (31004295168 bytes)
disk size: 0

# virt-clone -o rhel7.4 -n 16clone --file=/dev/sdc --check all=off
WARNING  This will overwrite the existing path '/dev/sdc'
Cloning rhel7.4-clone.qcow2  

# qemu-img info /dev/sdc
image: /dev/sdc
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

Result: 
i. Cloning begins without calculated size warning, it is as expected.
ii. New guest can boot up.


Scenario-3: block disk has 3 partitions, setting block_disk_size <3.9G (disk size of original guest)

# lsblk |grep sdc
sdc                         8:32   1  28.9G  0 disk 
├─sdc1                      8:33   1     2G  0 part 
├─sdc2                      8:34   1     1G  0 part 
└─sdc3                      8:35   1     9G  0 part 

Then select sdc1 as backend.

# virt-clone -o rhel7.4 -n sdc1 --file=/dev/sdc1 --check all=off
WARNING  This will overwrite the existing path '/dev/sdc1'
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 9216 M requested > 2048 M available
Cloning rhel7.4-clone.qcow2                                                                                                            | 2.0 GB  00:00:12 ... 

Clone 'sdc1' created successfully.

# qemu-img info /dev/sdc1
image: /dev/sdc1
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

Result: 
i. Cloning begins with calculated size '9216 M requested > 2048 M' in warning, it is as expected. But i'm concerned that whether the data in sdc2 or other partition will be overwritten since sdc1 is not big enough.
ii. New guest failed to boot into os(Please see Screenshot), so while cloning a guest, will virt-clone commands calculated size it at least needs?


@Pavel, i also have another question about Scenario-1 and Scenario-3, after cloning, the virtual disk size is 9.0G, exceeding to itself size(7.5G of sdb and 2.0G of sdc1), is it a bug, thanks.
Comment 7 zhoujunqin 2017-11-27 04:25:26 UTC 
Created attachment 1359289 [details]
Screenshot for guest 'sdc1'
Comment 8 Pavel Hrdina 2017-11-27 09:29:43 UTC 
Hi, for scenario 1 and 3 user have disabled all the checks which means
force clone the guest even if it might not work and might not fit into
the destination.  If something doesn't work it's not a bug, virt-clone
does exactly what user asked it to do.

In scenario 3 the guest didn't boot probably because the disk size
(the size, that is actually used) is 3.9G but the destination partition
is only 2G so virt-clone was not able to clone the whole disk.
Comment 9 zhoujunqin 2017-11-28 03:02:21 UTC 
To make verification steps and results more clear based on Comment 6 and Comment 8.

Try to verify this bug with new build:
virt-manager-1.4.3-2.el7.noarch
virt-install-1.4.3-2.el7.noarch

1. Prepare a health shutoff guest. 
...
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/rhel7.4-clone.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
...

Then check disk size.

# qemu-img info /var/lib/libvirt/images/rhel7.4-clone.qcow2 
image: /var/lib/libvirt/images/rhel7.4-clone.qcow2
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 3.9G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

Result: The actual size guest used is 3.9G.

2. Clone a guest using a real disk partition as backend storage.

scenairo-1 full_block_disk_size < 9G

# qemu-img info /dev/sdb
image: /dev/sdb
file format: raw
virtual size: 7.5G (8006926336 bytes)
disk size: 0


# virt-clone -o rhel7.4 -n 9-clone --file=/dev/sdb --check all=off
WARNING  This will overwrite the existing path '/dev/disk/by-path/pci-0000:00:1d.0-usb-0:1.3:1.0-scsi-0:0:0:0'
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 9216 M requested > 7636 M available
Cloning rhel7.4-clone.qcow2                                                                                          | 9.0 GB  00:03:39     

Clone '9-clone' created successfully.

# qemu-img info /dev/sdb
image: /dev/sdb
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false


Result:
i. Cloning begins with calculated size '9216 M requested > 7636 M' in warning, it is as expected.
ii. New guest can boot up.


Scenario-2: full_block_disk_size > 9G 

# qemu-img info /dev/sdc
image: /dev/sdc
file format: raw
virtual size: 29G (31004295168 bytes)
disk size: 0

# virt-clone -o rhel7.4 -n 16clone --file=/dev/sdc --check all=off
WARNING  This will overwrite the existing path '/dev/sdc'
Cloning rhel7.4-clone.qcow2  

# qemu-img info /dev/sdc
image: /dev/sdc
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

Result: 
i. Cloning begins without calculated size warning, it is as expected.
ii. New guest can boot up.


Scenario-3: block disk has 3 partitions, setting block_disk_size <3.9G (disk size of original guest)

# lsblk |grep sdc
sdc                         8:32   1  28.9G  0 disk 
├─sdc1                      8:33   1     2G  0 part 
├─sdc2                      8:34   1     1G  0 part 
└─sdc3                      8:35   1     9G  0 part 

Then select sdc1 as backend.

# virt-clone -o rhel7.4 -n sdc1 --file=/dev/sdc1 --check all=off
WARNING  This will overwrite the existing path '/dev/sdc1'
WARNING  The filesystem will not have enough free space to fully allocate the sparse file when the guest is running. 9216 M requested > 2048 M available
Cloning rhel7.4-clone.qcow2                                                                                                            | 2.0 GB  00:00:12 ... 

Clone 'sdc1' created successfully.

# qemu-img info /dev/sdc1
image: /dev/sdc1
file format: qcow2
virtual size: 9.0G (9663676416 bytes)
disk size: 0
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: true
    refcount bits: 16
    corrupt: false

Result:

i. Cloning begins with calculated size '9216 M requested > 2048 M' in warning, it is as expected.
ii. New guest failed to boot up, it is as expected, for the disk size
(the size, that is actually used) is 3.9G but the destination partition
is only 2G so virt-clone was not able to clone the whole disk.

Based on above three testing scenarios, move this bug from ON_QA to VERIFIED.
And also thanks for Pavel's help.
Comment 12 errata-xmlrpc 2018-04-10 11:40:46 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/RHEA-2018:0726
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