@rizaemet-0
Ever since I have changed to guessVhdSizeOnImport: true I have not had any problems. However I only backup 5 VMs which is not much.

In the past I noticed that if I didn't change the default "Concurrency" setting to 1 in the Backup NGs advanced settings (I assume that it tries to parallelize backups by default) then my tasks would fail randomly once in a while with VDI_IO_ERROR(Device I/O errors). I figured that perhaps my servers are not fast enough; they have about 40MB/s write speed to the disks only. Setting to 1 solved it, but I can imagine this may not be desirable if there is lots of VMs to backup since it would slow down the process considerably.

Hi,

I had noticed a similar problem. I have upgraded from XCP-NG 7.4 to 8.0 via the ISO. Upgrade was painless. Only issue was with a single VM not starting that was resolved with "xe vm-cd-eject --multiple".

I have also upgraded to the latest Xen Orchestra from sources:
:xo-server 5.46.0
:xo-web 5.46.0

I have 2 xenservers with local storage defined like this:
https://i.imgur.com/XCCyzS2.png

I have defined a simple Continous Replication task like this to backup a very small VM from xenserver1 to xenserver2:
https://i.imgur.com/d8nuDAN.png

And started the task manually, however it eventually fails like this:
https://i.imgur.com/B5IS5lB.png

Attached log:
https://pastebin.com/raw/gS9SYXgg

Changing the setting in config.toml of xo-server to: 'guessVhdSizeOnImport: true' seems to have fixed the problem (the backup task completes succesfully).

Thanks.