Thanks, ranochigo.  That's interesting, so potentially it could be dangerous, so perhaps the "warning" word is correct.  So the client is throwing a warning because it's completely in the dark but everyone else knows what it is.  I think I can live with that!

I am using the latest version of Bitcoin Core and I get the "warning" in the debug log.

Version:

"version": 190001,
"subversion": "/Satoshi:0.19.0.1/",

Warning:

"2020-01-31T13:48:49Z UpdateTip: new best=0000000000000000000b5b0e9239b0f34b17bd7127d8ea3e7df71fcff32c4da7 height=615367 version=0x20600000 log2_work=91.614776 tx=498470771 date='2020-01-31T13:48:17Z' progress=1.000000 cache=507.2MiB(3674023txo) warning='66 of last 100 blocks have unexpected version'"

I understand it's harmless but I don't like the look of it, particularly as I am not an expert in this field and any "warning" spooks me - especially if it's got anything to do with money!  I was pretty concerned when I first read it, so it was straight on to Google, ending up here (nice to be back btw).

If it must be reported, I think it could be phrased better.  Why be warned about something that is harmless??  Something like "info" or "notice" would be far better.  Would have saved me the time researching it and worrying about it!

Just wait a week.  Once it's downloaded, the updates (a new block every 10 minutes) are very small and fast.  If it gets bigger, you'll need to get a bigger disk!

You don't pay to download it.  I used an Amazon Web Services server instance for the download.  You need to pay for that.  I posted the costs for it above.  If you're using a PC on your home broadband it won't cost anything.

Well, it was worth a shot!  Maybe if it's that, or the end of Bitcoin...

Why not make a block every minute?  Make the reward 1.25 bitcoin so you still average 12.5 bitcoin every 10 minutes.  You still get 12.5 bitcoin every 10 minutes but you get 10 times the number of transactions confirmed.

Why stop at a minute, make a new block every 10 seconds, every second, again with a proportional reward to maintain the average of 12.5 bitcoin every 10 minutes?  could get a *lot* more transactions processed and more quickly.

Excellent information again, thank you.  Yes, I did notice those options when playing with the core but didn't fully understand them.  So you could set blockmintxfee to quite a high value to only accept transactions with large fees.  Very interesting, so it's the core that determines what transactions are available to miners, hence no setting for it on BFGMiner.  So if you are using someone else's core, you have to go with their settings.  I suppose this goes back to the early days when every miner would have their own core and the core (bitcoind) did the mining.

Bandwidth in, i.e. downloading the blockchain, is free.  Data transfer out is free for the first 1GB then $0.09 per GB after that.  Which would be expensive running as a full node if someone downloaded the entire blockchain of 172GB, would be ~ $15 every time (not sure if the transfer is measured in bits or bytes which could make a significant difference).  You wouldn't have any transfer out if you were using it privately, i.e. not accepting incoming requests/connections.  Plus, I believe data transfer between servers on the AWS network is free.

You pay for the storage.  I used 200GB of storage which is charged at $0.116 per GB per month, which equates to $23.20 for the month.

The server instance is one of their lower specs and costs $0.0264 per hour, which equates to (roughly) $19 a month.

The beauty of the AWS instances is that you can start and stop them at any time.  You only pay for what you use.  I have used this one for a few days just to download the blockchain and have a play with it.  In 5 1/2 days it's cost me $3.53 for the instance and around $5 for the storage.  My transfer out was 4.6GB, costing 42 cents (I was only accepting incoming connections for a few hours).  It's on a very good network too, so you should get good connectivity.

Do the mining programs automatically select the transactions with the highest fees?  Been looking at BFGMiner but didn't notice a configuration for this or any mention of it in the README.


Just been reading some very worrying articles about very high bitcoin transaction fees:

http://uk.businessinsider.com/bitcoin-payment-mining-fees-hit-new-high-2017-12
m/2017/12/19/big-transactions-fees-are-a-problem-for-bitcoin.html]https://www.c[Suspicious link removed]m/2017/12/19/big-transactions-fees-are-a-problem-for-bitcoin.html

...meaning no-one is going to use it to buy coffee or pizza.  One of the articles mentions Lightning Network with instant transactions and low fees, which to me looks very interesting.

Thanks all.  Good info!  I would like to keep a full node to help the network.  Just tinkering for now!

Thanks all for the very helpful replies.  I noticed the prune option but I wasn't sure about it (being very new to this).  My understanding was that you needed the full blockchain for maximum integrity.  What if everyone pruned their blockchain, would that mean there wouldn't be any full copies of the blockchain?!  Wouldn't that be a problem?

Yes, Jet Cash, I remember seeing an option to state the data directory.  That would be very handy to have the .bitcoin directory on a SSD.  Initially I was thinking you would just need the blocks and the chainstate data but it makes sense, and is a lot easier, simply to copy the entire directory.

Right.  I'm very new to this.  I wasn't thinking about the size of the chain so much as the size of the blocks.  What if there's tens of thousands, or hundreds of thousands of new transactions per block (as there will be when everyone starts using bitcoin on a regular basis!).  All those transactions in one block of 1MB?

Will be interesting to see how big it gets, with the increased popularity of bitcoin.

Wondering if the data files can simply be copied to another disk?  Would save downloading and processing everything again when it comes time to upgrade your system.

March 17th 2018.  Just for reference.

Just downloaded the entire blockchain.

Number of blocks: 513,962

Download time: 2 days 3 hours

Size on disk: 172GB

Used an Amazon Web Services EC2 t2.small server instance, running Ubuntu. 2GB memory.  Was struggling a bit, hence the download time.  CPU running at 100% constantly.  Memory was fine but I think more would be needed if running a faster processor.  Not sure of the CPU specs on the t2.small instance but it's one of their lowest performing (and cheapest) instances.

Fixed it.  The "configure" file didn't exist because autogen.sh encountered errors.  I needed to install a couple of packages so that autogen.sh would run properly.  When it did, it created the "configure" file.

Needed to install pkg-config and libgcrypt20-dev, like so:


I had previously installed all the recommended packages/dependencies which included pkg-config but not libgcrypt20-dev.

Getting a problem installing this.  States in the readme to run ./configure but I don't have a file by that name.  I do have configure.ac so tried running that, and got this: