Question about pruned node and docker.

[NinjaWaza]

Hello,
I am new in bitcoin and I wanted to run my own pruned node, to be able to don't trust but verify.
Because I don't have a lot of free space on my computer, I decided to run a pruned node, as I understand it is currently downloading blocks from the genesis block to the most up to date one, and it verify every transactions before checking and downloading the next block.
But because I set the option prune=550 in the configuration file it doesn't keep for ever every blocks information.

I am using docker for doing this : kylemanna/bitcoind (image name), my question is, to be able to spin up more quickly a new (pruned) node (on an other computer for example) can I just make a backup of the data folder of the container and just re use it, as I already personally verified the blockchain from the beginning (because, actually this process is taking a really long time IMO).

A totally different question is about the node, when this one will be synced with the network I will be able to use it to broadcast my transactions to the network right ?
And will I be able to see the amounts of btc my wallet hold even without the whole blockchain history ? My guess is that my node will ask to a random peer (a full node) and he could quickly verify just some block returned by the full node, but maybe I am totally wrong and it's not working like that.

In advance thank for your answer, and sorry for my English mistakes, as I am not a native English speaker.

[LoyceV]

A totally different question is about the node, when this one will be synced with the network I will be able to use it to broadcast my transactions to the network right ?

Yes. You can use a pruned Bitcoin Core node to make and broadcast transactions from your wallet.

And will I be able to see the amounts of btc my wallet hold even without the whole blockchain history ?

It depends:

• if you create a new wallet from your pruned Bitcoin Core, it works just fine.
• if you load an old wallet.dat, you may not be able to see all it's history.
• if you load an old wallet.dat before Bitcoin Core starts syncing, it will find all it's transactions during syncing and work just fine.

My guess is that my node will ask to a random peer (a full node) and he could quickly verify just some block returned by the full node, but maybe I am totally wrong and it's not working like that.

It doesn't work this way.

[NinjaWaza]

Oh crap I didn't know that, I would have connect my btc wallet to the node before syncing if I would know, thank you for your answers.

And what do you think about my idea with the docker and the folder backup/export ?

[LoyceV]

And what do you think about my idea with the docker and the folder backup/export ?

I can't really comment on that: I don't use docker.

[nc50lc]

My guess is that my node will ask to a random peer (a full node) and he could quickly verify just some block returned by the full node, but maybe I am totally wrong and it's not working like that.

No, yes, your node will scan its already verified blocks for transactions related to your currently loaded wallets before those get pruned.
So, even if it'll delete them once the prune size reached its limit, your wallet already know which transactions are yours.

This is also why it wont be able to rescan any old wallet backups that was synced past your node's 'prune height' or descriptors with older transactions than it.
Check $ bitcoin-cli getblockchaininfo for the "pruneheight" to see your rescanblockchain command "start_height" limit.

And what do you think about my idea with the docker and the folder backup/export ?

I don't use docker but if the entire .bitcoin datadir is included and restored to the correct directory, it should should work.
But the new machine's bitcoin.conf file must also contain "prune=<size>" or as a command line arg, the size can be different than what you originally set.

If you want reliability, you can easily test it to your other machine since its size is just a few Gigabytes after pruning. (it's mostly the UTXO set)
But make sure to do it only once Bitcoin Core is fully shutdown or it will cause issues.

[NinjaWaza]

I talked with chatgpt about how bitcoin is working ^^.
I think he says wrong things, but what he says is that because all the utxo are aroung 10 gb even if my bitcoin core node is pruned and don't keep every block on his disk, he will actually keep every utxo list, and he says that once my bitcoin node would have finish syncing with the network (even in prune mode) I would be able to see the balance of any wallet (even one create before I started my bitcoin core setup, 2 days ago in my situation).
What I don't understand here is why the bitcoin blockchain size is about 900 gb but every uxto are around 10 gb, what all those block contains if it's not just utxo, here we are talking about bitcoin and not ethereum or an other blockchain where we can execute function things like that (maybe I am totally wrong and I don't understand anything about crypto currencies and we can't do things like that on ethereum).

[hosemary]

but what he says is that because all the utxo are aroung 10 gb even if my bitcoin core node is pruned and don't keep every block on his disk, he will actually keep every utxo list

This is right.
Even if you run a pruned node, you have to keep the UTXO set.

and he says that once my bitcoin node would have finish syncing with the network (even in prune mode) I would be able to see the balance of any wallet (even one create before I started my bitcoin core setup, 2 days ago in my situation).

This is wrong.
If you load a new wallet.dat, you will have to redownload the blockchain, so that the transactions are displayed.

What I don't understand here is why the bitcoin blockchain size is about 900 gb but every uxto are around 10 gb, what all those block contains if it's not just utxo, here we are talking about bitcoin and not ethereum or an other blockchain where we can execute function things like that

The bitcoin blockchain includes all the transactions that have been made so far.
The UTXO set is much smaller in size, because it's just a list including some information about unspent outputs.

Each bitcoin transaction contains ID(s) of the parents along with the index of the output(s) that are spent, unlocking script(s), locking script(s), amount of output(s) and some other information that I may have forgotten to mention. All these data are recorded in the blockchain.

In UTXO set, we only have some information about unspent outputs like the ID of the transaction that has created the UTXO along with its index in the transaction, their amount and locking script.
Also note that UTXO stands for Unspent Transaction Output. Once a UTXO is spent, it's removed from the UTXO set.

[nc50lc]

-snip- and he says that once my bitcoin node would have finish syncing with the network (even in prune mode) I would be able to see the balance of any wallet (even one create before I started my bitcoin core setup, 2 days ago in my situation).

ChatGPT must have misunderstood the documentations stating that you can see the balance of any wallet as long as the node hasn't pruned the required blocks yet.

Here's the catch, remember the getblockchaininfo output that I've mentioned "pruneheight", it indicates the lowest (oldest) block height that your node can rescan.
The higher your prune size setting is, the lower it is from the tip of the blockchain since your node can store more blocks.
If the wallet that it needs to rescan requires the blocks older than it, your node has to redo IBD to do so.
But it'll load just fine if your node still has the blocks that it needs to rescan.