I'am trying to back up a Vm and i have the necessary disk space to do that ! but the process is always stopping on 30-40% and i got this error !
some help!
Also, could you post some more information? E.g. 'pveversion -v', your VM config ('qm config <vmid>'), which storage are you using, anything in logs (dmesg, journalctl, etc...)
Could it be that you're running two corosync (PVE) clusters in one network, potentially with the same name? Shouldn't affect your backup problems, but could explain the corosync related errors you're seeing.