This paper may be relevant to the topic http://people.cs.uchicago.edu/~teutsch/papers/repurposing_miners.pdf. The paper discusses an attack when miners in the network are rational. The paper shows that "a mining pool which controls at least 38.2% of the network’s total computational power can, with modest financial capacity, gain mining advantage over honest mining".

I'm trying to setup a local testnet with multiple nodes. Currently I have three nodes, and their mining powers are almost the same.

Things have been quite ok so far, except some problems that I need to ask from you.

When I try the getblocktemplate rpc call (because I later want to run a pool), it returns the message as in the title. For example:

although there are already 10 blocks in the blockchain maintained by the node. Its the same for other nodes as well. So why does that happen?

The nodes do not sync up very often although they are all connected together (each node has 2 inbound connections and 2 outbound connections). It is so often that one node is 2 block ahead of other and remains so for a long time. Thus, again, why does that happen? I thought after finding a valid block, the node will broadcast that to every connected node and the network will work on top of that block?

Please let me know if you can help answer either one or both the questions.

Thanks,

I asked the same question some time ago. Please go and get the answer yourself https://bitcointalk.org/index.php?topic=758979.msg8558976#msg8558976

I just found the answer in this this topic http://bitcoin.stackexchange.com/questions/12955/how-do-mining-pools-distribute-work-effectively.

Thanks for reading.

Hi,

I've been searching for that question in the forum but till now I haven't found any relevant thread. I bet that its been discussed somewhere, so please point me the thread and I will delete this one. If not, here my question in details.

The question is if there are N miners 1..N joining a pool with each having a hashrate h_i, so how does the pool operator distributes/manages the power properly? So as far as I understand how pooled mining works, the miner will get the block header via the get_work() request and mine on that to get valid shares/contributions. As my guess, the pool operator will distribute/manage the pool power though that get_work() request as well. However, there are several approaches for that.

1. The pool operator will specify some ranges of the nonce for miners to work on.
2. The pool operator will have some psudorandom function to generate the nonce and give miners different seeds.
3. The pool operator will let miners decide which nonce they should work.

My claim is that 3 won't work since if miner 1 submits a share S, other can submit S also without doing any work. And its not a good approach to optimize the pool power. Meanwhile 1 and 2 may work, but I'm not sure since miners join and leave the pool as they please. So I really want to know what is going on in real pools.

Thanks,

Btw, Dropbox now reduces the price for their pro package. Basically you can have 1TB with only $9.99 per month. Maybe you guys should calculate the effective cost again.