vzdump iothread

I would like to know if it's fine to set iothread to 0? I've just noticed that some of my backups failing causes of iothread was set to 1. any suggestions are greatly appreciated

I am seeing this in the backup log after I have enabled iothread: 111: Jul 29 05:15:03 ERROR: Backup of VM 111 failed - disk 'scsi0' (iothread=on) can't use backup feature currently. Please set backup=no for this drive at /usr/share/perl5/PVE/VZDump/QemuServer.pm line 74. Is this a feature or a...