Sorry, but it is not possible to investigate this issue without NAKIVO logs. Please, request support from NAKIVO web interface to send a new support bundle and create a ticket on NAKIVO support team. If you need any further information, please do not hesitate to contact us. Thank you in advance!
Official reply from support :
"All read/write operations to tape work with the switch off cache to guarantee that data will not be lost. That approach makes the read-write operation is slower than usual. You can try to change the tape block size to find more optimal for high speed."
Should I say something else, or are you kidding me?
If this is true , Nakivo is ruining every tapedrive over time, becaus everyone knows , that shoe-shining is bad for tape drives
One example of the speed, while copying to tape: ( This is not an exeption):
Over about 10 minutes there is written few to tape:
Meanwhile, there is almost no load on local disc-storage
@David Thank you for your question. According to the NAKIVO development roadmap, support of KVM virtualization (proxmox is KVM based) for virtual machine backup is planned. The estimated implementation dates are yet to be determined.