From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from <1240902@gmail.com>) id 1Yys6S-0000rq-OZ for bitcoin-development@lists.sourceforge.net; Sun, 31 May 2015 01:31:52 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.212.177 as permitted sender) client-ip=209.85.212.177; envelope-from=1240902@gmail.com; helo=mail-wi0-f177.google.com; Received: from mail-wi0-f177.google.com ([209.85.212.177]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Yys6R-0005Lx-IG for bitcoin-development@lists.sourceforge.net; Sun, 31 May 2015 01:31:52 +0000 Received: by wibut5 with SMTP id ut5so10804871wib.1 for ; Sat, 30 May 2015 18:31:45 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.180.76.100 with SMTP id j4mr8680305wiw.10.1433035905600; Sat, 30 May 2015 18:31:45 -0700 (PDT) Received: by 10.180.208.69 with HTTP; Sat, 30 May 2015 18:31:45 -0700 (PDT) In-Reply-To: References: <554BE0E1.5030001@bluematt.me> Date: Sun, 31 May 2015 09:31:45 +0800 Message-ID: From: Chun Wang <1240902@gmail.com> To: bitcoin-development@lists.sourceforge.net Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.4 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (1240902[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in digit (1240902[at]gmail.com) -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.0 LOTS_OF_MONEY Huge... sums of money -0.0 AWL AWL: Adjusted score from AWL reputation of From: address X-Headers-End: 1Yys6R-0005Lx-IG Subject: [Bitcoin-development] Fwd: Block Size Increase Requirements X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 31 May 2015 01:31:52 -0000 On Sat, May 30, 2015 at 9:57 PM, Gavin Andresen wrote: >> Bad miners could attack us and the network with artificial >> big blocks. > > > How? > > I ran some simulations, and I could not find a network topology where a big > miner producing big blocks could cause a loss of profit to another miner > (big or small) producing smaller blocks: > > http://gavinandresen.ninja/are-bigger-blocks-better-for-bigger-miners > > (the 0.3% advantage I DID find was for the situation where EVERYBODY was > producing big blocks). If someone propagate a 20MB block, it will take at best 6 seconds for us to receive to verify it at current configuration, result of one percent orphan rate increase. Or, we can mine the next block only on the previous block's header, in this case, the network would see many more transaction-less blocks. Our orphan rate is about 0.5% over the past few months. If the network floods 20MB blocks, it can be well above 2%. Besides bandwidth, A 20MB block could contain an average of 50000 transactions, hundred of thousands of sigops, Do you have an estimate how long it takes on the submitblock rpccall? For references, our 30Mbps bandwidth in Beijing costs us 1350 dollars per month. We also use Aliyun and Linode cloud services for block propagation. As of May 2015, the price is 0.13 U.S. dollars per GB for 100Mbps connectivity at Aliyun. For a single cross-border TCP connection, it would be certainly far slower than 12.5 MB/s. I think we can accept 5MB block at most. (sorry forgot to cc to the mailing list)