Hmm interesting, so without adding backing_fmt, if i enable the below in /etc/libvirt/qemu.conf, will it work ?
# If allow_disk_format_probing is enabled, libvirt will probe disk # images to attempt to identify their format, when not otherwise # specified in the XML. This is disabled by default. # # WARNING: Enabling probing is a security hole in almost all # deployments. It is strongly recommended that users update their # guest XML <disk> elements to include <driver type='XXXX'/> # elements instead of enabling this option. # #allow_disk_format_probing = 1 On Wed, Mar 18, 2015 at 5:33 PM, Shanzhi Yu <s...@redhat.com> wrote: > > > ------------------------------ > > *From: *"Deepak Shetty" <dpkshe...@gmail.com> > *To: *libvir-list@redhat.com > *Sent: *Wednesday, March 18, 2015 7:19:05 PM > *Subject: *[libvirt] Domain XML isn't dumping full backing chain > > > Hi, > I am using libvirt version 1.2.9.2 on F21 and i am unable to get the > complete backing chain info in the virsh dumpxml output. Details below : > > *My backing chain per qemu-img :* > > [stack@devstack-f21 test]$ qemu-img info --backing-chain snap4.qcow2 > image: snap4.qcow2 > file format: qcow2 > virtual size: 1.0G (1073741824 bytes) > disk size: 196K > cluster_size: 65536 > backing file: ./snap3.qcow2 > Format specific information: > compat: 1.1 > lazy refcounts: false > > image: ./snap3.qcow2 > file format: qcow2 > virtual size: 1.0G (1073741824 bytes) > disk size: 196K > cluster_size: 65536 > backing file: ./snap2.qcow2 (actual path: ././snap2.qcow2) > Format specific information: > compat: 1.1 > lazy refcounts: false > > image: ././snap2.qcow2 > file format: qcow2 > virtual size: 1.0G (1073741824 bytes) > disk size: 196K > cluster_size: 65536 > backing file: ./snap1.qcow2 (actual path: ./././snap1.qcow2) > Format specific information: > compat: 1.1 > lazy refcounts: false > > image: ./././snap1.qcow2 > file format: qcow2 > virtual size: 1.0G (1073741824 bytes) > disk size: 196K > cluster_size: 65536 > backing file: ./base.qcow2 (actual path: ././././base.qcow2) > Format specific information: > compat: 1.1 > lazy refcounts: false > > image: ././././base.qcow2 > file format: qcow2 > virtual size: 1.0G (1073741824 bytes) > disk size: 196K > cluster_size: 65536 > Format specific information: > compat: 1.1 > lazy refcounts: false > > If you want prepare the backing chain yourself, you should add "-o > backing_fmt=$farmat" options, > like "qemu-img create -f qcow2 base.s1 -b base.qcow2 -o backing_fmt=qcow2" > > I created 4 snapshots using commands (similar to the below, just dumping > the last one here ): > > [stack@devstack-f21 test]$ virsh snapshot-create-as test-domain > on-test-snap4 --disk-only --reuse-external --diskspec > hda,snapshot=external,file=/home/stack/test/snap4.qcow2 > Domain snapshot on-test-snap4 created > > [stack@devstack-f21 test]$ virsh domblklist test-domain > Target Source > ------------------------------------------------ > hda /home/stack/test/snap4.qcow2 > > > > virsh dumpxml test-domain|more > .... > > <disk type='file' device='disk'> > <driver name='qemu' type='qcow2' cache='none'/> > <source file='/home/stack/test/snap4.qcow2'/> > <backingStore type='file' index='1'> > <format type='raw'/> > > If you don't add "-o backing_fmt=qcow2", it will treat backing file format > as raw format. > Since a raw format file doesn't have a backing file, so you only see > snap4.qcow2 and > snap3.qcow2 > > > <source file='/home/stack/test/./snap3.qcow2'/> > <backingStore/> > </backingStore> > <target dev='hda' bus='ide'/> > <alias name='ide0-0-0'/> > <address type='drive' controller='0' bus='0' target='0' unit='0'/> > </disk> > > > ..... > > I think thats happening beccause the backingStore format is coming as 'raw' > What am i missing ? > > thanx, > deepak > > > -- > libvir-list mailing list > libvir-list@redhat.com > https://www.redhat.com/mailman/listinfo/libvir-list > > > > > -- > Regards > shyu >
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