Author

Topic: Alert: chain fork caused by pre-0.8 clients dealing badly with large blocks (Read 15422 times)

legendary
Activity: 1288
Merit: 1225
Away on an extended break
https://blockchain.info/en/orphaned-blocks

The bug appears to be resolved now. Merchants can accept transactions. Mining on 0.8 is OK, but do not increase the target block size.
legendary
Activity: 1288
Merit: 1225
Away on an extended break
Gavin just tweeted this:  https://twitter.com/gavinandresen/status/311315494214987778

And suggested we go here for more info:  http://bitcoin.org/chainfork.html


Quote
11/12 March 2013 Chain Fork Information

What happened
A bitcoin miner running version 0.8.0 created a large block (at height 225,430) that is incompatible with earlier versions of Bitcoin.

The result was a block chain fork, with miners, merchants and users running the new version of bitcoin accepting, and building on, that block, and miners, merchants and users running older versions of bitcoin rejecting it and creating their own block chain.

What is being done
Large mining pools running version 0.8.0 were asked to switch back to version 0.7, to create a single block chain compatible with all bitcoin software.

Questions & Answers
I'm not a miner or a merchant, what should I do?
Nothing. Your bitcoin software will switch to the correct chain automatically, no matter which version you are running.

Are my bitcoins safe?
Yes.

I'm a merchant accepting bitcoins, what should I do?
If you are running version 0.8.0, there is a small risk that payments with more than 6 confirmations could be double-spent on the 0.7-compatible blockchain. The risk is small because this is not a network split-- transactions are being sent to both sides of the chain split, and it is unlikely (but possible) that somebody could get two versions of the same transaction into the two sides of the chain.

What will be done
The core developers are investigating exactly what causes the old versions to reject the new blocks, and will release a 0.8.1 version that avoids creating blocks that are incompatible with older versions.
legendary
Activity: 1288
Merit: 1225
Away on an extended break
The original post lacked info for "regular users".  Here it is:

(1) If you are a "regular user" (not a miner), the best thing is to do nothing and wait a couple hours.  Upgrading, downgrading, whining, FUD, etc, will make no difference.
(2) If you are a "regular user", you don't need to upgrade downgrade or anything.  Just chill out
(3) Regardless of who you are, your transactions are not dead, your coins are not lost.  They will just temporarily be held up.  If you sent a transaction within the last few hours, it may take a few more hours before it's sorted out.
(4) If you insist on processing transactions right now it's probably best to wait 20+ confirmations.  It's just due diligence though ... an attacker would still need a tremendous amount of mining power, quick thinking, and a victim willing to part with a lot of BTC.
(5) By tomorrow this will be in the past and everything will appear to be normal again.  If you slept through this, you'd never know that anything happend (except for the price drop).

Let me reiterate, your coins are not at risk, your transactions are not lost.  It'll just take some time for the network to "iron itself out."  Everything will be okay.
legendary
Activity: 1288
Merit: 1225
Away on an extended break
Please note that funds traded on MT.Gox (MTGOXUSD, BTC etc) are perfectly safe as the BTC traded on Gox is not on the block-chain, only in Gox database, it's virtual BTC so to speak. The only time Gox touches the block chain is for deposits and withdrawals.
vip
Activity: 1052
Merit: 1055
http://pastebin.com/uUacVNHK

"The Bitcoin network is currently experiencing an irreconcilable fork
between Bitcoin 0.8 and <0.8 nodes due to a block being mined by a
Bitcoin 0.8 node which an elevated blocksize which older nodes are
unable to handled.
 
This issue will be resolved by mining power moving to the pre-0.8 fork
and making it longer.  Until this is resolved all transactions at and
beyond block 225439 should be regarded as unconfirmed.
 
Miners must move their hashpower back to 0.7.2 (or before) nodes or
their blocks will be orphaned.  Once the pre-0.8 chain is longer
operation will resume as normal and a patch will be issued for 0.8 to
avoid triggering this issue.
 
Please see the Bitcoin-dev mailing list or contact me if more
information is required. I will send out another email once the issue
is resolved."
legendary
Activity: 1288
Merit: 1225
Away on an extended break
Hello everyone,

there is an emergency right now: the block chain has split between 0.7+earlier and 0.8 nodes. I'll explain the reasons in a minute, but this is what you need to know now:
  • After a discussion on #bitcoin-dev, it seems trying to get everyone on the old chain again is the least risky solution.
  • If you're a miner, please do not mine on 0.8 code. Stop, or switch back to 0.7. BTCGuild is switching to 0.7, so the old chain will get a majority hash rate soon.
  • If you're a merchant: please stop processing transactions until the chains converge.
  • If you're on 0.7 or older, the client will likely tell you that you need to upgrade. Do not follow this advise - the warning should go away as soon as the old chain catches up.
  • If you are not a merchant or a miner, don't worry.
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