What would happen if a part or segment was lost in the network?

[arrogantrabbit]

@asturking

how many copies were sent to the nodes

Zero. There are no copies. Each node holds a unique erasure-encoded shard.

@Dominick

When you upload or download from the network, file segments are sent one after another. However, the pieces that make the segments are sent in parallel. Much effort has gone into optimizing this process, for instance when you download a file we attempt to grab 39 pieces when only 29 are required eliminating slow nodes (Long Tail Elimination). This is our base parallelism and allows up to 10 nodes to respond slowly without affecting your download speeds.

When uploading we start with sending 110 erasure-coded pieces per segment in parallel out to the world but stop at 80. This has the same effect as above in eliminating slow nodes (Long Tail Elimination).