Sometimes initial backups complete, sometime not.
For example I wiped my backup storage today in my lab system and created new backup schedule. VDR started to backup guests, three was completed without problems but three did not ever complete, and I did wait long time. All backups were started at same time and VMs are very close to eachother in size vise.
I was able to stop hanging backup processes and VDR started backup for two missed VMs again, lets see how it goes this time.
Update: Now some of backups completed. But still one of three backups were significantly slower than others, it didn't even speed up after other backups complete.
I see from logs that normal backup speed is 1 gigabyte/minute, these forever running backups report speed of ~50 megabytes/minute. Problem is CPU load, but why slow backups won't gain speed after resources are freed from completed backups?