@pierrebrunet I inadvertently found more information yesterday. I installed an old e492b commit on a new machine, configured identically to the original, and got a different error but the same effect. The new error is:
xcp xo backup Error: read ETIMEDOUT
That lead me to this page:
https://xcp-ng.org/forum/topic/10799/backup-timeout-error
I moved the XO machine onto the same subnet as XCP, leaving the storage behind in a different network. This fixed the issue, at least on commit e492b ... I have not yet tried it on the new release... however I am pretty confident it will be successful.
If I'm honest, I think this is a tuning issue between XO and XCP. XO is now mounting an NFS share across this subnet boundary and that mount is not having any sort of performance issue, but for some reason XO times out transferring the same data from dom0? That seems off to me.
It's not a probem moving XO to the other subnet, so I've done that, but maybe this deserves a look in the future.
