search for: lazy_refcounts

Hi All I was reading through this: http://kashyapc.com/2011/12/02/little-more-disk-io-perf-improvement-with-fallocateing-a-qcow2-disk/ I was basically searching for pointers on improving disk I/O. I wanted to know the purpose of preallocation=full & preallocation=metadata , What is the difference between them ? and which one would yield a better disk I/O speed ? Appreciate your

...tadata': allocates qcow2 metadata, and it's still a sparse image. $ qemu-img create -f qcow2 -o preallocation=metadata test1-metadata.qcow2 1G Formatting 'test1-metadata.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off refcount_bits=16 328K -rw-r--r--. 1 root root 1.1G Jun 3 03:20 copy-test1-metadata.qcow2 (2) 'preallocation=full': allocates zeroes and makes a non-sparse image. $ qemu-img create -f qcow2 -o preallocation=full test2-full.qcow2 1G Formatting 'test2-full.qcow2', fm...

...m is CentOS Linux release 7.6.1810 (Core) with libvirt-4.5.0-10.el7_6.4.x86_64 Please let me know if I am missing something. Thanks. # create base file [root@singularity images]# qemu-img create base.qcow2 8G -f qcow2 Formatting 'base.qcow2', fmt=qcow2 size=8589934592 cluster_size=65536 lazy_refcounts=off refcount_bits=16 [root@singularity images]# qemu-img info base.qcow2 image: base.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 17K cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false...

...libguestfs: command: run: \ -o backing_fmt=raw libguestfs: command: run: \ /tmp/libguestfsm4E1E4/snapshot1 Formatting '/tmp/libguestfsm4E1E4/snapshot1', fmt=qcow2 size=4294967296 backing_file='/tmp/.guestfs-36/root.4124' backing_fmt='raw' encryption=off cluster_size=65536 lazy_refcounts=off libguestfs: command: run: qemu-img libguestfs: command: run: \ create libguestfs: command: run: \ -f qcow2 libguestfs: command: run: \ -b /tmp/bV8yUVWwXU libguestfs: command: run: \ -o backing_fmt=raw libguestfs: command: run: \ /tmp/libguestfsm4E1E4/snapshot2 Formatting '/tmp/libguestfsm4E...

Hi, What's the difference between QEMU snapshot and libvirt snapshot? # qemu-img create -f qcow2 disk.img 512 Formatting 'disk.img', fmt=qcow2 size=512 encryption=off cluster_size=65536 lazy_refcounts=off # qemu-img info disk.img image: disk.img file format: qcow2 virtual size: 512 (512 bytes) disk size: 136K cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false # /usr/bin/qemu-system-ppc -M ppce500 -enable-kvm -m 512 -nographic -kernel /dev/shm/uImage -ini...

2017-11-15 23:55 GMT+01:00 Max Reitz <mreitz@redhat.com>: > https://xanclic.moe/convert-xva.rb -- does this work? > (It seems to works on the two example images I found...) > > An example is in the code, you use it like this: > > $ ./convert-xva.rb ~/Downloads/stats-appliance-2.36.020502.xva Ref:73 It doesn't work on huge images: # time convert-xva.rb

...;Copying disk %d/%d to %s (%s)") - (i+1) nr_disks t.target_file t.target_format; - if verbose () then printf "%s%!" (string_of_target t); - - (* We noticed that qemu sometimes corrupts the qcow2 file on - * exit. This only seemed to happen with lazy_refcounts was - * used. The symptom was that the header wasn't written back - * to the disk correctly and the file appeared to have no - * backing file. Just sanity check this here. - *) - let overlay_file = t.target_overlay.ov_overlay_file in -...

....x86_64 qemu-system-x86-1.6.2-6.fc20.x86_64 I adapted your commands to my conf: # qemu-img create -f qcow2 -o preallocation=metadata /home/kvmimages/f20vm 4G Formatting '/home/kvmimages/f20vm', fmt=qcow2 size=4294967296 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off # virt-install --name f20vm --disk /home/kvmimages/f20vm --cdrom /home/kvmimages/Fedora-20-x86_64-DVD.iso --memory 2048 WARNING CDROM media does not print to the text console by default, so you likely will not see text install output. You might want to use --location. Début d'installat...

...ot/libguestfs/tmp/libguestfs9gclsg/overlay1.qcow2 Formatting '/root/libguestfs/tmp/libguestfs9gclsg/overlay1.qcow2', fmt=qcow2 size=8589934592 backing_file=rbd:images/CentOS-7-x86_64-GenericCloud-1901:mon_host=[fd00\:\:cefc\:1]\:6789:auth_supported=none backing_fmt=raw cluster_size=65536 lazy_refcounts=off refcount_bits=16 libguestfs: trace: disk_create = 0 libguestfs: trace: add_drive = 0 Welcome to guestfish, the guest filesystem shell for editing virtual machine filesystems and disk images. Type: ‘help’ for help on commands       ‘man’ to read the manual       ‘quit’ to quit the shell &g...

...cking_file=/home/peterd/TVE/wer.qcow2,backing_fmt=qcow2 libguestfs: command: run: \ /tmp/libguestfsUIZbDK/overlay1.qcow2 Formatting '/tmp/libguestfsUIZbDK/overlay1.qcow2', fmt=qcow2 size=107374182400 backing_file=/home/peterd/TVE/wer.qcow2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 libguestfs: error: command: waitpid: No child processes libguestfs: error: qemu-img: /tmp/libguestfsUIZbDK/overlay1.qcow2: qemu-img exited for an unknown reason (status -1), see debug messages above libguestfs: trace: disk_create = -1 (error) libguestfs: trace: add_drive = -1 (...

Hello, I am curious why when using virt-sparsify the apparent-size of the file gets reduced to the actual file size? Is there a way to get the apparent-size left as the full size? In the man page for virt-sparsify it has a section on "IMPORTANT NOTE ABOUT SPARSE OUTPUT IMAGES" and its output seems to indicate what I would expect where "ls -lh" shows the full apparent size

Hello, I am curious why when using virt-sparsify the apparent-size of the file gets reduced to the actual file size? Is there a way to get the apparent-size left as the full size? In the man page for virt-sparsify it has a section on "IMPORTANT NOTE ABOUT SPARSE OUTPUT IMAGES" and its output seems to indicate what I would expect where "ls -lh" shows the full apparent size

...ally, you'd use it like this: $ ./convert-xva-online.rb ~/Downloads/stats-appliance-2.36.020502.xva Ref:73 81936 M $ qemu-img create -f qcow2 [whatever options you need] disk1.qcow2 \ 81936M Formatting 'disk1.qcow2', fmt=qcow2 size=85916123136 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 $ ./convert-xva-online.rb ~/Downloads/stats-appliance-2.36.020502.xva \ Ref:73 \ '{"driver":"qcow2", "detect-zeroes":"unmap", "discard":"unmap", "file":{"driver":"...

...</compat> </target> </volume> Or request some feature that implies v3: <volume> <name>demo.qcow2</name> <capacity>1073741824</capacity> <target> <format type='qcow2'/> <features> <lazy_refcounts/> </features> </target> </volume> and pass this XML to virsh vol-create > It is possible to create a new volume using qcow2 version 3 (compat=1.1) > format *using libvirt/virsh* (I know I can do that via qemu-img)? Any > drawback on using version 3 forma...

...s in libgfapi source code to encryption so I decided to try it out. While attempting to create an image: # qemu-img create -f qcow2 gluster://gluster01/virt0/testing.img 30G Formatting 'gluster://dalpinfglt01/virt0/testing.img', fmt=qcow2 size=32212254720 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 [2017-06-02 18:30:37.489831] E [mem-pool.c:579:mem_put] (-->/lib64/libglusterfs.so.0(syncop_lookup+0x4e5) [0x7f2abbe66d35] -->/lib64/libglusterfs.so.0(+0x59f02) [0x7f2abbe62f02] -->/lib64/libglusterfs.so.0(mem_put+0x190) [0x7f2abbe54a60] ) 0-mem-pool: mem-pool ptr is N...

...wrote: [. . .] > I adapted your commands to my conf: > > # qemu-img create -f qcow2 -o preallocation=metadata /home/kvmimages/f20vm > 4G > Formatting '/home/kvmimages/f20vm', fmt=qcow2 size=4294967296 encryption=off > cluster_size=65536 preallocation='metadata' lazy_refcounts=off > # virt-install --name f20vm --disk /home/kvmimages/f20vm --cdrom > /home/kvmimages/Fedora-20-x86_64-DVD.iso --memory 2048 > WARNING CDROM media does not print to the text console by default, so you > likely will not see text install output. You might want to use --location. >...

...erd/TVE/wer.qcow2,backing_fmt=qcow2 > libguestfs: command: run: \ /tmp/libguestfsUIZbDK/overlay1.qcow2 > Formatting '/tmp/libguestfsUIZbDK/overlay1.qcow2', fmt=qcow2 > size=107374182400 backing_file=/home/peterd/TVE/wer.qcow2 backing_fmt=qcow2 > encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 > libguestfs: error: command: waitpid: No child processes > libguestfs: error: qemu-img: /tmp/libguestfsUIZbDK/overlay1.qcow2: qemu-img > exited for an unknown reason (status -1), see debug messages above Obviously waitpid(2) is failing with ECHILD here: https://gith...

...of corruption there too. I'm building the initial guest image qcow2 for those guest VMs this way: 1) start with a rhel-guest image (currently rhel-server-7.6-update-5-x86_64-kvm.qcow2) 2) convert to LVM by doing this: qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=1048576,lazy_refcounts=off final_guest.qcow2 512G virt-format -a final_guest.qcow2 --partition=mbr --lvm=/dev/rootdg/lv_root --filesystem=xfs guestfish --ro -a rhel_guest.qcow2 -m /dev/sda1 -- tar-out / - | \ guestfish --rw -a final_guest.qcow2 -m /dev/rootdg/lv_root -- tar-in - / 3) use "final_guest.qcow2&q...

A lot of code runs 'qemu-img create' or 'truncate' to create blank disk images. In the past I resisted adding an API to do this, since it essentially duplicates what you can already do using other tools (ie. qemu-img). However this does simplify calling code quite a lot since qemu-img is somewhat error-prone to use (eg: don't try to create a disk called "foo:bar")

...correctly, then everything is working as it should. For qcow2 files, the virtual size is not related to the "apparent" size, as you can easily prove: $ qemu-img create -f qcow2 huge.qcow2 1T Formatting 'huge.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 $ ls -lh huge.qcow2 -rw-r--r--. 1 rjones rjones 208K Jun 17 09:09 huge.qcow2 If you use raw files, then the file apparent size and virtual size are the same. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtu...