Description of problem:

rhv-image-discrepancies uses this on each SPM per DC:
DUMP_VOLUME_CHAINS = "vdsm-tool dump-volume-chains {sd_id} -o json -f {sd_id}"

But json output is always to STDOUT, never to file. So the "-f" parameter is ignored as "-f" is only meaningful if the output is sqlite, see below:

# vdsm-tool dump-volume-chains -h
usage: vdsm-tool [-h] [-u] [-H HOST] [-o {text,json,sqlite}] [-p PORT]
                 [-f SQLITE_FILE]
                 sd_uuid

positional arguments:
  sd_uuid               storage domain UUID

optional arguments:
  -h, --help            show this help message and exit
  -u, --unsecured       use unsecured connection
  -H HOST, --host HOST
  -o {text,json,sqlite}, --output {text,json,sqlite}
                        select output format
  -p PORT, --port PORT
  -f SQLITE_FILE, --sqlite-file SQLITE_FILE                 <------------
                        sqlite3 db output file


Version-Release number of selected component (if applicable):
rhv-log-collector-analyzer-0.2.15-0.el7ev.noarch

This is harmless, but could have a clean-up, for example:
DUMP_VOLUME_CHAINS = "vdsm-tool dump-volume-chains {sd_id} -o json"