Try using VDSM hooks https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.4/htm... I am using vdsm-hook-diskunmap as model. dnf install vdsm-hook-diskunmap cp /usr/libexec/vdsm/hooks/before_vm_start/50_diskunmap /usr/libexec/vdsm/hooks/before_vm_start/99_max_sectors After editing the file, the result is bellow # on host egrep -v \^$ /usr/libexec/vdsm/hooks/before_vm_start/99_max_sectors #!/usr/bin/python3 from __future__ import absolute_import from __future__ import print_function ''' Hook to set max_sectors on SCSI controller, virtio-scsi model Syntax: max_sectors=(256|128|64) Example: max_sectors=256 ''' import os import sys import traceback from xml.dom import minidom import hooking def addmax_sectors(domxml): max_sectorsConfig = os.environ['max_sectors'] for controller in domxml.getElementsByTagName('controller'): model = controller.getAttribute('model') if (model == 'virtio-scsi'): driver = controller.getElementsByTagName('driver')[0] driver.setAttribute('max_sectors', max_sectorsConfig) def main(): if 'max_sectors' in os.environ: max_sectorsConfig = os.environ['max_sectors'] domxml = hooking.read_domxml() if (max_sectorsConfig == '256' or max_sectorsConfig == '128' or max_sectorsConfig == '64'): addmax_sectors(domxml) hooking.write_domxml(domxml) def test(): text = '''<controller type='scsi' index='0' model='virtio-scsi'> <driver queues='2' iothread='1'/> <alias name='ua-c410327a-e4af-482a-966b-12cff96fea06'/> <address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/> </controller>''' xmldom = minidom.parseString(text) controller = xmldom.getElementsByTagName('controller')[0] print("\nController device definition before execution: \n%s" % controller.toxml(encoding='UTF-8')) addmax_sectors(xmldom) print("\nController device after setting max_sectors attribute: \n%s" % controller.toxml(encoding='UTF-8')) if __name__ == '__main__': try: if '--test' in sys.argv: test() else: main() except: hooking.exit_hook(' max_sectors hook: [unexpected error]: %s\n' % traceback.format_exc()) # on oVirt hosted engine # list current VM custom properties engine-config -l # add VM custom properties engine-config -s UserDefinedVMProperties='max_sectors=^(256|128|64)$' --cver=4.6 # check VM custom properties engine-config -g UserDefinedVMProperties systemctl restart ovirt-engine.service For me it's working with max_sectors 256