On Fri 11 Sep 2020 04:30:45 PM CEST, Bryan S Rosenburg wrote: > $ qemu-img --version > qemu-img version 4.2.0 (Debian 1:4.2-3ubuntu6.4) > Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers > > $ qemu-img create -f qcow2 prealloc_4G_2M.qcow2 4G -o > preallocation=full,cluster_size=2M > Formatting 'prealloc_4G_2M.qcow2', fmt=qcow2 size=4294967296 > cluster_size=2097152 preallocation=full lazy_refcounts=off > refcount_bits=16 > > $ qemu-img check prealloc_4G_2M.qcow2 > ERROR: coffset=0x1ffff80a00000: copied flag must never be set for > compressed clusters
I can reproduce that problem with 4.2.0 from Ubuntu but not with QEMU 3.1.0 nor with the latest master (post-5.1.0). I will investigate, it looks like it would need a fix for Ubuntu LTS. Berto
