libguestfs support snapshot based virutal disk analysis?
Hi dear all: I have browsed almost all architecture of libGuestFs and use it on Fedora 18. It really seems greate! However, 1. No virtual disk (*.vdi, *.vmdk...) based snashot analysis code Current LibGuestFs could recognize and virtual disk format (e.g. *.VDI) and the file syste inside it (e.g. NTFS ), but find no support for snapshot virtual disk. Virtual Machine such VirtualBox will generate snapshot (*.VDI for virtual disk diff, *.sav for virtual memory diff), and these snapshots are always diff towards based virtutual disk. 2. So I missed this feature? Or these feature not supported now? If not support, so does libguestFs will support it in the future? What is the effort or difficulty for this part development? Or you have any other opitions? Thnaks very much for your kind reply. Best regards
On Sun, Jun 09, 2013 at 03:40:42PM +0800, 雨居轩 wrote:
Hi dear all: I have browsed almost all architecture of libGuestFs and use it on Fedora 18. It really seems greate! However, 1. No virtual disk (*.vdi, *.vmdk...) based snashot analysis code Current LibGuestFs could recognize and virtual disk format (e.g. *.VDI) and the file syste inside it (e.g. NTFS ), but find no support for snapshot virtual disk.
libguestfs relies on qemu for all disk / format support. So we support whatever qemu supports. As qemu doesn't appear to be able to read snapshots (except for the "top" one obviously) from a VMDK or VDI file, we can't read them either. If support for this was added to qemu, then libguestfs would get it for free, or nearly for free.
Virtual Machine such VirtualBox will generate snapshot (*.VDI for virtual disk diff, *.sav for virtual memory diff), and these snapshots are always diff towards based virtutual disk.
2. So I missed this feature? Or these feature not supported now? If not support, so does libguestFs will support it in the future?
It totally depends on qemu. You or someone would have to add this feature to qemu. libguestfs would get it for free after that. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org
I've used QEMU to read .vmdk snapshots. The VM directory layout in my case (Fusion, and I've seen Workstation do the same) created a .vmdk file per snapshot, and qemu-img could use that .vmdk file and the base .vmdk to convert the disk image to a raw image. IIRC there is a manifest file that ties .vmdk files to the snapshot they represent. So, from my experience, qemu does read disk snapshots in the .vmdk format. It might need a little extending to also look for and parse that manifest file, to treat a directory with .vmdk's as a snapshot tree. Does this help? --Alex On Sunday, June 9, 2013, Richard W.M. Jones wrote:
On Sun, Jun 09, 2013 at 03:40:42PM +0800, 雨居轩 wrote:
Hi dear all: I have browsed almost all architecture of libGuestFs and use it on Fedora 18. It really seems greate! However, 1. No virtual disk (*.vdi, *.vmdk...) based snashot analysis code Current LibGuestFs could recognize and virtual disk format (e.g. *.VDI) and the file syste inside it (e.g. NTFS ), but find no support for snapshot virtual disk.
libguestfs relies on qemu for all disk / format support. So we support whatever qemu supports. As qemu doesn't appear to be able to read snapshots (except for the "top" one obviously) from a VMDK or VDI file, we can't read them either. If support for this was added to qemu, then libguestfs would get it for free, or nearly for free.
Virtual Machine such VirtualBox will generate snapshot (*.VDI for virtual disk diff, *.sav for virtual memory diff), and these snapshots are always diff towards based virtutual disk.
2. So I missed this feature? Or these feature not supported now? If not support, so does libguestFs will support it in the future?
It totally depends on qemu. You or someone would have to add this feature to qemu. libguestfs would get it for free after that.
Rich.
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org
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On Sun, Jun 09, 2013 at 05:49:44PM -0400, Alexander Nelson wrote:
I've used QEMU to read .vmdk snapshots. The VM directory layout in my case (Fusion, and I've seen Workstation do the same) created a .vmdk file per snapshot, and qemu-img could use that .vmdk file and the base .vmdk to convert the disk image to a raw image. IIRC there is a manifest file that ties .vmdk files to the snapshot they represent.
So, from my experience, qemu does read disk snapshots in the .vmdk format. It might need a little extending to also look for and parse that manifest file, to treat a directory with .vmdk's as a snapshot tree.
Are these real VMDK files, or do you mean the "vmdk" files which are really raw that ESX produces? TBH I don't know a lot about the VDMK format, except that the specifications are intimidating. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW
(Sorry, Rich, I managed to miss reply-all.) These VMDK files are difference files from a baseline VMDK file. I'm not familiar with ESX's storage, but the size indicators on these tell me they aren't raw. For a virtual disk that has 3.2GB of data in its current state, against 3.0GB of data in its baseline, the current state's .vmdk file is 200MB. --Alex On Mon, Jun 10, 2013 at 6:11 AM, Richard W.M. Jones <rjones@redhat.com>wrote:
On Sun, Jun 09, 2013 at 05:49:44PM -0400, Alexander Nelson wrote:
I've used QEMU to read .vmdk snapshots. The VM directory layout in my case (Fusion, and I've seen Workstation do the same) created a .vmdk file per snapshot, and qemu-img could use that .vmdk file and the base .vmdk to convert the disk image to a raw image. IIRC there is a manifest file that ties .vmdk files to the snapshot they represent.
So, from my experience, qemu does read disk snapshots in the .vmdk format. It might need a little extending to also look for and parse that manifest file, to treat a directory with .vmdk's as a snapshot tree.
Are these real VMDK files, or do you mean the "vmdk" files which are really raw that ESX produces?
TBH I don't know a lot about the VDMK format, except that the specifications are intimidating.
Rich.
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW
On Mon, Jun 10, 2013 at 10:03:59AM -0400, Alex Nelson wrote:
(Sorry, Rich, I managed to miss reply-all.)
These VMDK files are difference files from a baseline VMDK file.
I'm not familiar with ESX's storage, but the size indicators on these tell me they aren't raw. For a virtual disk that has 3.2GB of data in its current state, against 3.0GB of data in its baseline, the current state's .vmdk file is 200MB.
OK well I guess we don't support these. My answer however is the same as before. Support has to be added to qemu, then we'll get it for free. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v
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Alexander Nelson
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雨居轩