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Date: Mon, 17 Aug 2015 05:15:15 -0400
From: jl2012@xbt.hk
To: Luv Khemani <luvb@hotmail.com>
In-Reply-To: <BLU172-W10F7A109C917CD56E7DF4DC2790@phx.gbl>
References: <BLU172-W10F7A109C917CD56E7DF4DC2790@phx.gbl>
Message-ID: <239f3c2d796a1abf337d9a4228e19e26@xbt.hk>
User-Agent: Roundcube Webmail/1.0.5
Cc: bitcoin-dev@lists.linuxfoundation.org
Subject: Re: [bitcoin-dev] Miners are struggling with blocks far smaller
 than 750KB blocks and resorting to SPV mining
Precedence: list

The traffic between the pool server and individual hashers is far busier 
than 50kB/30s. If their bandwidth is so limited, hashers would have 
switched to other pools already.

All these data may prove is they have very bad mining codes. For 
example, their hashers may not be required to update the transaction 
list regularly. I don't think they are struggling. They are just too 
lazy or think that's too risky to improve their code. After all, they 
are generating half million USD per day and a few seconds of downtime 
would hurt.

By the way, vast majority of the full blocks (>0.99MB) on the blockchain 
are generated by Chinese pools.

Luv Khemani via bitcoin-dev 於 2015-08-17 04:42 寫到:
> Hi all,
> 
>  I previously mentioned in a post that i believe that technically
> nodes are capable of handling blocks an order of magnitude larger than
> the current blocksize limit, the only missing thing was an incentive
> to run them. I have been monitoring the blockchain for the past couple
> of weeks and am seeing that even miners who have all the incentives
> are for whatever reason struggling to download and validate much
> smaller blocks.
> 
> The data actually paints a very grim picture of the current
> bandwidth/validating capacity of the global mining network.
> 
> See the following empty blocks mined despite a non-trivial elapsed
> time from the previous block just from the past couple of days alone
> (Data from insight.bitpay.com):
> 
> EmptyBlock /Time since previous block/ Size of previous
> block(bytes)/Mined by
> ====================================================370165 29s 720784
> Antpool
> 370160 31s 50129 BTCChinaPool
> 370076 49s 469988 F2Pool
> 370059 34s 110994 Antpool
> 370057 73s 131603 Antpool
> 
> We have preceding blocks as small as 50KB with 30s passing and the
> miner continues to mine empty blocks via SPV mining.
> The most glaring case is Block 370057 where despite 73s elapsing and
> the preceding block being a mere 131KB, the miner is unable to
> download/validate fast enough to include transactions in his block.
> Unless ofcourse the miner is mining empty blocks on purpose, which
> does not make sense as all of these pools do mine blocks with
> transactions when the elapsed time is greater.
> 
> This is a cause for great concern, because if miners are SPV mining
> for a whole minute for <750KB blocks, at 8MB blocks, the network will
> just fall apart as a significant portion of the hashing power SPV
> mines throughout. All a single malicious miner has to do is mine an
> invalid block on purpose, let these pools SPV mine on top of them
> while it mines a valid block free of their competition. Yes, these
> pools deserve to lose money in that event, but the impact of reorgs
> and many block orphans for anyone not running a full node could be
> disastrous, especially more so in the XT world where Mike wants
> everyone to be running SPV nodes. I simply don't see the XT fork
> having any chance of surviving if SPV nodes are unreliable.
> 
> And if these pools go out of business, it will lead to even more
> mining centralization which is already too centralized today.
> 
> Can anyone representing these pools comment on why this is happening?
> Are these pools on Matt's relay network?
> 
> 
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