When a file is downloaded by a customer, the application will request pieces from more than the minimum required number of nodes necessary to reconstitute the entire file. By default, only 29 pieces of 80 are needed to reconstruct the file, so when a download is initiated, the system will first request pieces from 35 nodes, but as soon as the required number of 29 pieces has been successfully downloaded, the remaining partial downloads from slower nodes will be aborted. Note that the customer can change the default settings configured in uplink library/CLI as needed for their use case.
So, if your node is offline when a download is attempted, the network will just use the pieces downloaded from other nodes to reconstitute the file. If your node fails to respond to a valid download request, you will not earn STORJ for the egress bandwidth and your node reputation will be impacted.
To be considered a reliable storage node operator, you should keep your uptime above 99.3% which translates to a maximum of about 5 hours 6 minutes and 48.2 seconds of downtime a month.
Please read more on the blog Early feedback from V3 storage node operators: You’ve got questions, we’ve got answers!