I think the philosophy behind is that if 75% of the miners agree and fork, the other 25% will follow rapidly and start mining on the majority chain because they'd be losing money by mining on the minority chain. IMO it's a little too low :/

i said in the last line of my post, the risk that i am talking about is the risk of splitting the network into two separate chains.


is it your own understanding/guess or do you have a reference for that
i'll admit i haven't had time to go through it myself and do a proper research yet.

Bitcoin Unlimited does not have an "activation".  It is already active.  Anyone can run Bitcoin Unlimited right now and declare whatever blocksize they want to support.

Miners can already create larger blocks if they want to.  Those blocks will be orphaned if there are not enough other miners that are willing to support that block height yet (which would make it foolish for a miner to waste money mining a block that won't ever pay them).  If there are enough miners supporting the larger block then the block size will increase.

thanks for the explanation franky, i can understand the orphan risk and the relationship with the percentages when put it like that.

but what about risk of splitting the network into two chains.
this is what my question basically is, i don't know how right or off the mark i am though.
i say with 95% the remaining 5% can not really stay around for long and they either die or switch.
but with 75% the remaining 25% seems too big and can stick around and continue producing blocks

It might be a little bit too low but 95% is crazy in my opinion.  Most people will jump onto something if it's clear that a large enough majority of Bitcoiners has chosen something that it's unlikely anyone will be able to change it, but there will always be a group of stubborn people who believe the worst of that system and refuse to adopt it.  This group will nearly definitely be over 5% but under 25%.

It might even be SegWit's unrealistic goal that has resulted in BU overtaking SegWit's adoption among miners (along with the support from Jihan Wu).

Ideally though it would somewhere in between the two, maybe about 90%.

no
the 5% minority see the blockheight (bu being higher) request the blockheight. see its a rule breaker to the 5%. reject it
and again
the 5% minority see the blockheight (bu being higher) request the blockheight. see its a rule breaker to the 5%. reject it
and again
(which as you say is 5% not syncing and either die(stuck) or change to the majority to rejoin)

---

the 25% minority see the blockheight (bu being higher) request the blockheight. see its a rule breaker to the 25%. reject it
and again
the 25% minority see the blockheight (bu being higher) request the blockheight. see its a rule breaker to the 25%. reject it
and again
(which as you say is 25% not syncing and either die(stuck) or change to the majority to rejoin)
meaning in short MORE nodes having the headache. but in both cases no second chain(just 1 chain and some dead nodes(the less the % the less dead nodes)

for the 5% or 25% to build on a LOWER height. they have to ignore (ban) dis-commnicate split from the majority. to then only see the minority as the highest height. to then sync to that without the orphan game of unsyncing them.

this is called a bilateral split (intentional ban).
consensus mechanism (orphaning) exist for a good reason. to keep one chain that the majority can agree on.
to make a second chain exist and survive without orphans requires avoiding the majority by banning from it, to not see the majority blockheight, to then not fight it

even ethereum done this by their '--oppose-dao-fork' to know which nores to white list and which nodes to blacklist to avoid orphan drama and only see the blockheigh of the chain they prefer

It's not just 75% - the first phase is 75% for a full difficulty adjustment period.

When they stay at 75% for a full difficulty adjustment period then they will start broadcasting willingness to mine a bigger block.

When enough have signalled intent to accept bigger blocks for a full adjustment period WITHOUT dropping below 75% then they will start mining bigger blocks.

That's what I have seen them posting, so it will take maintaining 75% consensus for several difficult adjustment periods BEFORE the first bigger blog.

The only thing that could throw a wrench in that is UASF in which case they may need to emergency hard fork earlier.

FTFY


if blockstream want to ban anything thats not blockstream then they can play on their 26% hashpower(today stats) all they like. and pretend its achieved 100% by just ignoring the other 74% of the network.. they are still going to be on a minority and less height altcoin chain.

Why waste your time writing this:


When you could just be honest and admit that this is the real "consensus mechanism" in BU:



....which is just an invitation to an endless string of noisy, shouty 51% fork after 51% fork?




Alice Wonder, why aren't you able to present clear, honest arguments?