[ovirt-users] Incremental backup using ovirt api

Hi, I tried to take incremental backup of a vm using this script. public function downloadDiskIncremental(){ $data=array(); $xmlStr = "<disk_attachment> <disk id='1371afdd-91d4-4bc7-9792-0efbf6bbd1c9'> <backup>incremental</backup> </disk> </disk_attachment>"; $curlParam=array( "url" => "vms/4044e014-7e20-4dbc-abe5-64690ec45f63/diskattachments", "method" => "POST", "data" =>$xmlStr, ); } But it is throwing me error as Array ( [status] => error [message] => For correct usage, see: https://ovirt.bobcares.com/ovirt-engine/api/v4/model#services/disk-attach... Please help me with this issue....