Simon, What is happening is that when we create a preallocated disk on NFS, we fill the file with zeros in order to "allocate" the space. However, while copying the disk we use qemu-img that will ignore the zeros.
Quick way to demonstrate: [root@white-vdsd test]# dd if=/dev/zero of=myfile.txt bs=1M count=1 1+0 records in 1+0 records out 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.00172084 s, 609 MB/s [root@white-vdsd test]# du -h myfile.txt 1.0M myfile.txt [root@white-vdsd test]# ls -lh myfile.txt -rw-r--r-- 1 root root 1.0M Aug 7 12:39 myfile.txt [root@white-vdsd test]# qemu-img convert myfile.txt myfile2.txt [root@white-vdsd test]# ls -lh myfile2.txt -rw-r--r-- 1 root root 1.0M Aug 7 12:41 myfile2.txt [root@white-vdsd test]# du -h myfile2.txt 0 myfile2.txt [root@white-vdsd test]# qemu-img info myfile.txt image: myfile.txt file format: raw virtual size: 1.0M (1048576 bytes) disk size: 1.0M [root@white-vdsd test]# qemu-img info myfile2.txt image: myfile2.txt file format: raw virtual size: 1.0M (1048576 bytes) disk size: 0 I hope this explains what you see. Regards, Fred On Sun, Aug 7, 2016 at 11:13 AM, Simon Barrett < [email protected]> wrote: > Storage is NFS. What logs would you like to see? > > Many thanks. > > Simon > > > > On Sun, Aug 7, 2016 at 8:53 AM +0100, "Fred Rolland" <[email protected]> > wrote: > > Simon hi, > > What storage type are you using in source and target storage domains ? > (NFS, ISCSI....) > > Can you share the logs? > > Thanks, > Fred > > On Fri, Aug 5, 2016 at 6:37 PM, Simon Barrett < > [email protected]> wrote: > >> Another example. This one was moved to a new storage domain >> >> >> >> root@ovirt_host1> qemu-img info dd6f25f6-7830-4024-915f-a20268797c34 >> >> image: dd6f25f6-7830-4024-915f-a20268797c34 >> >> file format: raw >> >> virtual size: 200G (214748364800 bytes) >> >> disk size: 5.0G >> >> >> >> root@ ovirt_host1> cat dd6f25f6-7830-4024-915f-a20268797c34.meta >> >> DOMAIN=53560d43-874a-49c5-9c5a-8b90487c79f8 >> >> VOLTYPE=LEAF >> >> CTIME=1470305678 >> >> FORMAT=RAW >> >> IMAGE=741976cd-d1cb-4031-bdbe-6a745dff16ef >> >> DISKTYPE=2 >> >> PUUID=00000000-0000-0000-0000-000000000000 >> >> LEGALITY=LEGAL >> >> MTIME=0 >> >> POOL_UUID= >> >> SIZE=419430400 >> >> TYPE=PREALLOCATED >> >> DESCRIPTION= >> >> EOF >> >> >> >> >> >> This one has not been moved: >> >> >> >> [email protected]> qemu-img info 155f0d33-c280-4236-8d1e-fcb88f9a1242 >> >> image: 155f0d33-c280-4236-8d1e-fcb88f9a1242 >> >> file format: raw >> >> virtual size: 90G (96636764160 bytes) >> >> disk size: 90G >> >> >> >> [email protected]> cat 155f0d33-c280-4236-8d1e-fcb88f9a1242.meta >> >> DOMAIN=59bde2ff-e10d-477e-91c1-6355abff0999 >> >> CTIME=1464946639 >> >> FORMAT=RAW >> >> DISKTYPE=2 >> >> LEGALITY=LEGAL >> >> SIZE=188743680 >> >> VOLTYPE=LEAF >> >> DESCRIPTION={"DiskAlias":"ny2-laa-010.prod_Disk1","DiskDescription":""} >> >> IMAGE=82158182-81a4-458e-a41b-663756962666 >> >> PUUID=00000000-0000-0000-0000-000000000000 >> >> MTIME=0 >> >> POOL_UUID= >> >> TYPE=PREALLOCATED >> >> EOF >> >> >> >> See the mismatch between “virtual size” and “disk size” on the one that >> was moved. >> >> >> >> TIA, >> >> >> >> Simon >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *Simon Barrett >> *Sent:* Friday, 5 August, 2016 10:25 >> *To:* [email protected] >> *Subject:* [ovirt-users] preallocated storage issue? >> >> >> >> If I create a preallocated disk for a VM, I see the disk image file >> listing as the size I requested (100G): >> >> >> >> cd /rhev/data-center/mnt/storage_host1:_vol_pa1__nas__01b__oVir >> t__prod__01/53560d43-874a-49c5-9c5a-8b90487c79f8/images/d97f >> 7706-3662-40bf-9358-80e0dc51bff4 >> >> root@ovirt_host> ls -l >> >> total 105064644 >> >> -rw-rw---- 1 vdsm kvm 107374182400 Aug 5 10:57 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b >> >> -rw-rw---- 1 vdsm kvm 1048576 Aug 5 10:57 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b.lease >> >> -rw-r--r-- 1 vdsm kvm 313 Aug 5 10:57 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b.meta >> >> >> >> and the corresponding space used on disk matches >> >> >> >> root@ ovirt_host > du -sh * >> >> 101G 75c14559-e18f-4cc8-a3fe-bc0de507720b >> >> 1.1M 75c14559-e18f-4cc8-a3fe-bc0de507720b.lease >> >> 4.0K 75c14559-e18f-4cc8-a3fe-bc0de507720b.meta >> >> >> >> If I then migrate that storage (while the VM is shutdown) to a new >> storage domain, the size on disk does not match the allocated size. In this >> case there is nothing in the disk yet so it shows as 0. >> >> >> >> cd /rhev/data-center/mnt/storage_host2:_vol_pa1__ovirt__uatprod >> /1f2c2b48-1e77-4c98-a6da-5dc09b78cead/images/d97f7706- >> 3662-40bf-9358-80e0dc51bff4 >> >> root@ ovirt_host> ls -l >> >> total 1032 >> >> -rw-rw---- 1 vdsm kvm 107374182400 Aug 5 11:06 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b >> >> -rw-rw---- 1 vdsm kvm 1048576 Aug 5 11:06 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b.lease >> >> -rw-r--r-- 1 vdsm kvm 313 Aug 5 11:06 >> 75c14559-e18f-4cc8-a3fe-bc0de507720b.meta >> >> >> >> root@ ovirt_host > du -sh * >> >> 0 75c14559-e18f-4cc8-a3fe-bc0de507720b >> >> 1.1M 75c14559-e18f-4cc8-a3fe-bc0de507720b.lease >> >> 4.0K 75c14559-e18f-4cc8-a3fe-bc0de507720b.meta >> >> >> >> oVirt still lists the disk as preallocated in the GUI but it is in fact >> thin provisioned. >> >> >> >> I see the same issue if I clone a preallocated VM. The size on disk ends >> up being the equivalent of a thin-provisioned disk. I also had the issue >> when importing VM’s from an export domain when I had selected preallocated >> in the import dialog box. >> >> >> >> Is this a known issue? Should preallocated not mean preallocated on >> physical disk? >> >> >> >> Ovirt Engine is running 3.6.4.1-1.el6 >> >> >> >> The ovirt nodes are running: >> >> >> >> OS Version: RHEL - 7 - 2.1511.el7.centos.2.10 >> >> Kernel Version: 3.10.0 - 327.4.5.el7.x86_64 >> >> KVM Version: 2.3.0 - 31.el7_2.7.1 >> >> LIBVIRT Version: libvirt-1.2.17-13.el7_2.2 >> >> VDSM Version: vdsm-4.17.23.2-0.el7.centos >> >> SPICE Version: 0.12.4 - 15.el7 >> >> GlusterFS Version: [N/A] >> >> CEPH Version: librbd1-0.80.7-3.el7 >> >> >> >> Many thanks, >> >> >> >> Simon >> >> _______________________________________________ >> Users mailing list >> [email protected] >> http://lists.ovirt.org/mailman/listinfo/users >> >> >
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