Transcript for #bitcoin-dev 2017/07/28

05:46 jamesob where in this algorithm describes the creation of new side branches (i.e. prev_block_hash is in the main chain but not the tip, and not in any existing side branches)?
15:00 mmgen MMGen, the command-line wallet for geeks, now supports Segwit!
15:00 mmgen
18:58 Mad7Scientist 2017-07-28 18:57:36 ERROR: CheckBlock(): hashMerkleRoot mismatch
18:58 Mad7Scientist 2017-07-28 18:57:36 ERROR: ConnectTip(): ConnectBlock 0000000000000000a1f9ebf7133fd368bb4378b2ca4aba31975127bc5cf1f3b6 failed
18:58 Mad7Scientist I think I have a bad block
18:58 Mad7Scientist Could someone have done a DoS attack on me to stop Bitcoin?
18:58 Mad7Scientist It just keeps showing that erro
18:58 arubi Mad7Scientist, can you output that block and paste it somewhere?
18:58 arubi was that relayed to you?
18:59 Mad7Scientist It is hung on activating best chain
18:59 Mad7Scientist 2017-07-28 18:25:46 ERROR: CheckBlock(): hashMerkleRoot mismatch
18:59 Mad7Scientist 2017-07-28 18:25:46 Misbehaving: (8268900 -> 8269000)
18:59 Mad7Scientist 2017-07-28 18:25:46 ERROR: ConnectTip(): ConnectBlock 0000000000000000a1f9ebf7133fd368bb4378b2ca4aba31975127bc5cf1f3b6 failed
18:59 Mad7Scientist That's the original error before I restarted bitcoin-qt
18:59 arubi oh huh, it's on main chain
19:00 Mad7Scientist arubi, I don't know much about it
19:00 arubi might be data corruption.. try running with -reindex I guess
19:00 Mad7Scientist THis is version 0.12
19:00 Mad7Scientist I've been having trouble with the latest version too
19:00 Mad7Scientist but that may have been a hard drive problem
19:01 arubi yea Mad7Scientist that's a pretty old block
19:01 Mad7Scientist I don't know what to do
19:02 kinlo Mad7Scientist: a lot of problems like that are caused by bad hardware, as bitcoin is extreamly demanding on the hardware... are you sure about yur hardware?
19:02 Mad7Scientist Well it seems to be fine
19:02 Mad7Scientist memtest completed without error
19:03 Mad7Scientist and I'm trying a different hard drive now
19:03 Mad7Scientist Usually it is very rare for any hard drive to produce an error
19:03 kinlo actually, bitrot is very common
19:03 kinlo the percentage of errors goes down, but since our disksizes grow much faster, you will end up seeing more errors
19:03 Mad7Scientist So maybe a valid CRC error slipped through the hard drive?
19:04 Mad7Scientist I guess i'll reindex then
19:04 Mad7Scientist It's the only thing I can do I guess
19:04 Mad7Scientist IT took a whole day to get to this block
19:05 Mad7Scientist bincap, arubi go ahead with -reindex?
19:05 kinlo nowadays downloading is not the big issue, you might want to just try with a new wallet dir to test
19:06 Mad7Scientist WHat could be wrong with the old wallet dir?
19:06 Mad7Scientist It's only one day and this error hasn't come up before
19:06 kinlo dunnow :) if it is bad hardware, it could be anything that is in that dir
19:06 Mad7Scientist reindex will fix all of that
19:07 kinlo I don't know if a reindex will fully revalidate the blocks
19:07 arubi Mad7Scientist, if you think your dive might be faulty, then no
19:07 Mad7Scientist not faulty just a single bit error
19:07 Mad7Scientist It's a new drive
19:09 arubi then I guess you could try. just copy important data out of it first..
19:09 kinlo Mad7Scientist: a filesystem like zfs or btrfs could prevent any problems and remove doubts, as those filesystems checksum the data