=== 16:34:08 virt-v2v em /NFS01/migrate/IT003629-IAAS-FV-WCI/IT003629-IAAS-FV-WCI-raw.qcow2 ===
image: /NFS01/migrate/IT003629-IAAS-FV-WCI/IT003629-IAAS-FV-WCI-raw.qcow2
file format: qcow2
virtual size: 150 GiB (161061273600 bytes)
disk size: 61.2 GiB
cluster_size: 65536
Format specific information:
    compat: 1.1
    compression type: zlib
    lazy refcounts: false
    refcount bits: 16
    corrupt: false
    extended l2: false
Child node '/file':
    filename: /NFS01/migrate/IT003629-IAAS-FV-WCI/IT003629-IAAS-FV-WCI-raw.qcow2
    protocol type: file
    file length: 61.2 GiB (65757380608 bytes)
    disk size: 61.2 GiB
virt-v2v: virt-v2v 2.4.0 (x86_64)
libvirt version: 10.0.0
libguestfs: trace: set_verbose true
libguestfs: trace: set_verbose = 0
libguestfs: trace: get_backend
libguestfs: trace: get_backend = "direct"
check_host_free_space: large_tmpdir=/var/tmp free_space=1028235264
virt-v2v: error: insufficient free space in the conversion server temporary directory /var/tmp (980.6M).

Either free up space in that directory, or set the LIBGUESTFS_CACHEDIR environment variable to point to another directory with more than 1GB of free space.

See also the virt-v2v(1) manual, section "Minimum free space check in the host".
rm -rf -- '/tmp/v2v.vGxZi6'
libguestfs: trace: close
libguestfs: closing guestfs handle 0x63eb03ec13c0 (state 0)
=== 16:34:08 virt-v2v rc=1 ===
ABORT virt-v2v