Re: [Libguestfs] Question about mounting QCOW2 files....
[Adding libguestfs mailing list]
On Sun, Oct 14, 2018 at 11:53:17AM -0400, Raghuram Devarakonda wrote:
Hi,
My name is Raghuram Devarakonda and I am a big fan of "nbdkit". I have
successfully used it to prototype (using Python plugin) a complex
project in our company and since then, I have also been trying to
understand and learn "guestfs-tools" as well. I have a question in
this regard and I hope you don't mind my sending mail gratuitously.
In our project, we deal with quite large sparse files whose total size
runs into several hundred terabytes or even more, though actual
allocated size on disk is much smaller. The problem is that such large
files present issues for copying around, compression, or even for
computing checksums. I am wondering of I can use guestfs-tools to
mount a QCOW2 image and then use the image as sparse file. The idea is
that actual file on the disk would be compact though to our code,
sparse file interface is preserved.
It's not very clear to me exactly what you want, but in general yes
qcow2 is a good way to handle very large, sparse disk images.
If you can be clearer about exactly what you mean by "mount" then I
could answer the question better. For example, do you mean "mount a
filesystem in the qcow2 image"? In which case use guestmount. If you
mean "attach the qcow2 disk as a local device" then qemu-nbd can do
this.
Rich.
Can you please let me know if this is possible? Can I mount a sparse
file using guestfs-tools even though it is not really a disk?
Thanks in advance,
Raghu
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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