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Description of problem:

qcow2 supports compressed images.  The default is zlib, but zstd is
also supported upstream.  However zstd compression is not enabled
in RHEL qemu-kvm at all, meaning that we cannot create, open etc
qcow2 zstd-compressed images.

Fedora and other distributions may switch to zstd compression for
qcow2, and this will create an interoperability issue in future.

Version-Release number of selected component (if applicable):

qemu-img-8.0.0-7.el9.x86_64

How reproducible:

100%

Steps to Reproduce:

$ qemu-img create -f qcow2 test.qcow2 1G -o compression_type=zstd
Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zstd size=1073741824 lazy_refcounts=off refcount_bits=16
qemu-img: test.qcow2: Parameter 'compression-type' does not accept value 'zstd'

On Fedora this works:

$ qemu-img create -f qcow2 test.qcow2 1G -o compression_type=zstd
Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zstd size=1073741824 lazy_refcounts=off refcount_bits=16

The change to the spec file is trivial, just use:

--enable-zstd

However there is an issue that this enables zstd-compressed live migration
support, which we do not wish to support (although zlib-compressed live
migration is already enabled and unsupported).

Kevin WDYT? I am wondering that is it worth taking extra maintenance burden at this point of time. Who is planning to create and distribute zstd compressed images.

Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 120 days