In the torrent file,every chunk(or piece) has a SHA1 hash.
Sure, this hash is used for verification because public network is unreliable.
In a private network, if all peers is reliable, should this hash been ignored, i.e skip chunk verification in client ?
Is there other consideration about using hash? e.g. network transfer error or software bug.
question from:https://stackoverflow.com/questions/65932730/why-bittorrent-need-chunk-hash
In a private network, if all peers is reliable
Hardware is never 100% reliable. At large scale you're going to see random bitflips everywhere. TCP and UDP only have weak checksums that will miss a bit flip happening in flight every now and then. Memory may not be protected by ECC. Storage might not even be protected by checksums.
So eventually there will be some corruption go uncaught if data isn't verified.
Generic SHA1 software implementations already are quite fast and should be faster than most common network or storage systems. With specialized SHA1 instructions in recent CPUs the cost of checksumming should become even lower, assuming the software makes use of them.
So generally speaking the risk of bitrot is not worth the very tiny decrease in CPU load. There might be exceptional situations where that is not the case, but it would be up to the operator of that specific system to measure the impact and decide whether he can accept bitrot to save a few CPU cycles.
