Re: Can centralised pools point their hashpower at a p2pool node?
I've been mulling this one over, and honestly, I'm not sure it's such a good idea, at least not with p2pool in its current state.
Let's assume for the sake of discussion that a large pool does shift their entire backend to p2pool overnight.
First off, it doesn't preclude any pool of a sufficiently large size from conducting a 51% attack, even with p2pool as an intermediary. (I bring this up because preventing a 51% attack is frequently cited as a reason for switching to p2pool.) The p2pool share chain is consensus based, just like the bitcoin blockchain. Thus, the way a 51% attack works is still just as applicable with p2pool as it is with any other system. The attacking pool simply has more hashpower than the rest of the p2pool network combined, and their share of the overall network hash rate is still the same as what it was before the shift to p2pool.
Second, it would immediately render p2pool useless for smaller miners. Let me give an example with simplified numbers (but still close to reality). The current network speed is on the order of 100Ph/s, or 100,000 Th/s. p2pool itself is registering on the order of 500Th/s, or 0.5% of the network speed. To get one share per day on p2pool, you need about 5Gh/s at present, or approximately 1/100,000 of the overall hash power of p2pool (again, simplified numbers, don't go crazy over my math!
). Now let's assume that a pool with 20Ph/s shifts to p2pool. p2pool's total hash rate jumps to a whopping 40 times its previous hash rate, and to get one share per day, you'd need over 200Gh/s. So if you have less than that on p2pool, you essentially stop getting shares, which means you get less payouts. It doesn't matter if the p2pool network is now finding 40 blocks a day or more; if you as an individual miner are sitting at zero shares, then you get zero payout. You'd be better off solo mining and hoping to hit a jackpot -- or joining a competing pool.
That said, if you have sufficient hashpower yourself to continue getting at least one share per day, this would be a great situation. Your variance would go down hugely, and while you'd earn much less per individual block found, you'd get many more payments per day as the network will find more blocks.
Let's assume for the sake of discussion that a large pool does shift their entire backend to p2pool overnight.
First off, it doesn't preclude any pool of a sufficiently large size from conducting a 51% attack, even with p2pool as an intermediary. (I bring this up because preventing a 51% attack is frequently cited as a reason for switching to p2pool.) The p2pool share chain is consensus based, just like the bitcoin blockchain. Thus, the way a 51% attack works is still just as applicable with p2pool as it is with any other system. The attacking pool simply has more hashpower than the rest of the p2pool network combined, and their share of the overall network hash rate is still the same as what it was before the shift to p2pool.
Second, it would immediately render p2pool useless for smaller miners. Let me give an example with simplified numbers (but still close to reality). The current network speed is on the order of 100Ph/s, or 100,000 Th/s. p2pool itself is registering on the order of 500Th/s, or 0.5% of the network speed. To get one share per day on p2pool, you need about 5Gh/s at present, or approximately 1/100,000 of the overall hash power of p2pool (again, simplified numbers, don't go crazy over my math!
). Now let's assume that a pool with 20Ph/s shifts to p2pool. p2pool's total hash rate jumps to a whopping 40 times its previous hash rate, and to get one share per day, you'd need over 200Gh/s. So if you have less than that on p2pool, you essentially stop getting shares, which means you get less payouts. It doesn't matter if the p2pool network is now finding 40 blocks a day or more; if you as an individual miner are sitting at zero shares, then you get zero payout. You'd be better off solo mining and hoping to hit a jackpot -- or joining a competing pool.That said, if you have sufficient hashpower yourself to continue getting at least one share per day, this would be a great situation. Your variance would go down hugely, and while you'd earn much less per individual block found, you'd get many more payments per day as the network will find more blocks.