<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, May 30, 2015 at 9:31 PM, Chun Wang <span dir="ltr"><<a href="mailto:1240902@gmail.com" target="_blank">1240902@gmail.com</a>></span> wrote:<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">
If someone propagate a 20MB block, it will take at best 6 seconds for<br>
us to receive to verify it at current configuration, result of one<br>
percent orphan rate increase.</span></blockquote><div><br></div><div>That orphan rate increase will go to whoever is producing the 20MB blocks, NOT you.</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class=""> Or, we can mine the next block only on<br>
the previous block's header, in this case, the network would see many<br>
more transaction-less blocks.<br></span></blockquote><div><br></div><div>Are you sure that is the best strategy? If a big block is slow to propagate, I suspect it will be better to punish the miner that created it by refusing to build on it until it has been fully validated.</div><div><br></div><div>I'll try to find time to run a couple of simulations.</div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">
<br>
Our orphan rate is about 0.5% over the past few months. If the network<br>
floods 20MB blocks, it can be well above 2%. Besides bandwidth, A 20MB<br>
</span>block could contain an average of 50000 transactions, hundred of<br>
<span class="">thousands of sigops, Do you have an estimate how long it takes on the<br>
submitblock rpccall?<br></span></blockquote><div><br></div><div>I can benchmark it. It should be pretty fast, and sipa has a couple of patches pending to make the UTXO cache much faster.</div><div><br></div><div>It can be fast because the vast majority of the work of validating all those transactions can happen as they are received into the memory pool.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">For references, our 30Mbps bandwidth in Beijing costs us 1350 dollars<br>
per month.</span></blockquote><div><br></div><div>You should be able to handle 20MB blocks no problem; if I round up to 100MB per block that works out to 1.3Mbps.</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class=""> We also use Aliyun and Linode cloud services for block<br>
propagation. As of May 2015, the price is 0.13 U.S. dollars per GB for<br>
100Mbps connectivity at Aliyun.</span></blockquote><div><br></div><div>That speed will handle 20MB blocks no problem.</div><div><br></div><div>If each 20MB block is 100MB of data up/down the wire (I'm vastly over-estimating, after optimization it should be 40MB) then you'll be paying...uhhh:</div><div><br></div><div>0.1 GB / block-data-on-wire * 144 blocks/day * 30.5 days/month * 0.13 $ / GB = $57</div><div><br></div><div>Less than $2 per day in bandwidth, surely you can afford that.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class=""> For a single cross-border TCP<br>
connection, it would be certainly far slower than 12.5 MB/s.</span> </blockquote><div><br></div><div>That's OK, you'll 1.3Mbps or less.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">
I think we can accept 5MB block at most.<br></span></blockquote><div><br></div><div>Are you worried about paying too much, or do 20MB blocks "feel like too much" ?</div><div><br></div></div>-- <br><div class="gmail_signature">--<br>Gavin Andresen<br></div>
</div></div>