I'd like to know this too. Is it just that a 4MB blockmaxweight would theoretically allow ~4MB blocks (if ~all witness data), which is too big? Or is there a more subtle reason we still need blockmaxsize after a HF? On May 30, 2017 9:28 AM, "Jorge Timón via bitcoin-dev" < bitcoin-dev@lists.linuxfoundation.org> wrote: Why not simply remove the (redundant after sw activation) 1 mb size limit check and increasing the weight limit without changing the discount or having 2 limits? On Wed, May 24, 2017 at 1:07 AM, Erik Aronesty via bitcoin-dev wrote: > Personally, I would prefer if a 2MB lock-in that uses BIP103 for the timing. > > I think up to 20% per year can be absorbed by averages in bandwidth/CPU/RAM > growth, of which bandwidth seems the most constraining. > > - Erik > > > On Tue, May 23, 2017 at 4:23 PM, Luke Dashjr via bitcoin-dev > wrote: >> >> In light of some recent discussions, I wrote up this BIP for a real 2 MB >> block >> size hardfork following Segwit BIP148 activation. This is not part of any >> agreement I am party to, nor anything of that sort. Just something to >> throw >> out there as a possible (and realistic) option. >> >> Note that I cannot recommend this to be adopted, since frankly 1 MB blocks >> really are still too large, and this blunt-style hardfork quite risky even >> with consensus. But if the community wishes to adopt (by unanimous >> consensus) >> a 2 MB block size hardfork, this is probably the best way to do it right >> now. >> The only possible way to improve on this IMO would be to integrate it into >> MMHF/"spoonnet" style hardfork (and/or add other unrelated-to-block-size >> HF >> improvements). >> >> I have left Author blank, as I do not intend to personally champion this. >> Before it may be assigned a BIP number, someone else will need to step up >> to >> take on that role. Motivation and Rationale are blank because I do not >> personally think there is any legitimate rationale for such a hardfork at >> this >> time; if someone adopts this BIP, they should complete these sections. (I >> can >> push a git branch with the BIP text if someone wants to fork it.) >> >> 
>> BIP: ?
>> Layer: Consensus (hard fork)
>> Title: Post-segwit 2 MB block size hardfork
>> Author: FIXME
>> Comments-Summary: No comments yet.
>> Comments-URI: ?
>> Status: Draft
>> Type: Standards Track
>> Created: 2017-05-22
>> License: BSD-2-Clause
>>
>> >> ==Abstract== >> >> Legacy Bitcoin transactions are given the witness discount, and a block >> size >> limit of 2 MB is imposed. >> >> ==Copyright== >> >> This BIP is licensed under the BSD 2-clause license. >> >> ==Specification== >> >> Upon activation, a block size limit of 2000000 bytes is enforced. >> The block weight limit remains at 4000000 WU. >> >> The calculation of block weight is modified: >> all witness data, including both scriptSig (used by pre-segwit inputs) and >> segwit witness data, is measured as 1 weight-unit (WU), while all other >> data >> in the block is measured as 4 WU. >> >> The witness commitment in the generation transaction is no longer >> required, >> and instead the txid merkle root in the block header is replaced with a >> hash >> of: >> >> 1. The witness reserved value. >> 2. The witness merkle root hash. >> 3. The transaction ID merkle root hash. >> >> The maximum size of a transaction stripped of witness data is limited to 1 >> MB. >> >> ===Deployment=== >> >> This BIP is deployed by flag day, in the block where the median-past time >> surpasses 1543503872 (2018 Nov 29 at 15:04:32 UTC). >> >> It is assumed that when this flag day has been reached, Segwit has been >> activated via BIP141 and/or BIP148. >> >> ==Motivation== >> >> FIXME >> >> ==Rationale== >> >> FIXME >> >> ==Backwards compatibility== >> >> This is a hardfork, and as such not backward compatible. >> It should not be deployed without consent of the entire Bitcoin community. >> Activation is scheduled for 18 months from the creation date of this BIP, >> intended to give 6 months to establish consensus, and 12 months for >> deployment. >> >> ==Reference implementation== >> >> FIXME >> >> >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev