Hi,
So After some tests:
I tried to download files with with ratio > 1 -> ok with ratio < 1 -> failed
So my story:
I upload files to backup it
I paid by allowing SCs for the service
I reach a ratio > 2.2 for all files
I close SIA UI for few days
I open it again
Ratio of some files is below 1
My understanding was if a node left network and don't respect the contract I got SCs back + collateral and the network try to find other node to keep ratio high enough.
My mistake was to close the sia-ui for few days, but it isn't very useful to keep a service always up if you just backup files.
I have a node for "selling" space but for each contract I paid for collateral.
Conclusion I paid to backup I paid to share and my backup isn't reliable.
I think something is wrong in the model.
Regards