[bitcoind] several bitcoind instances with one blockchain

[w4cky]

hi,
I wanted to give my server users the ability to run their own bitcoind instances without the need to duplicate the downloaded blockchain for each of the bitcoind instances.
I want to save space on HDD in this way. We need to have 10 bitcoind instances (each user has his own wallet.dat). I can run bitcoind on other ports but I do not know how to make him use one blockchain. The datadir parametr does not help.

is it possible what he wants to do? or is there any other way?

[darosior]

hi,
I wanted to give my server users the ability to run their own bitcoind instances without the need to duplicate the downloaded blockchain for each of the bitcoind instances.
I want to save space on HDD in this way. We need to have 10 bitcoind instances (each user has his own wallet.dat). I can run bitcoind on other ports but I do not know how to make him use one blockchain. The datadir parametr does not help.

is it possible what he wants to do? or is there any other way?

Hi,

maybe the multi-wallet support is what you are looking for.

[w4cky]

from what he writes on the page you link I will have the same port and the same login and password for rpc, and I want to have separate instances. Separate RPC

[Pmalek]

I managed to find a thread from a few years where this was discussed and I quoted some of the replies for you, hope it helps.
This is the original thread where this was discussed back in 2016.
https://bitcointalk.org/index.php?topic=1340309.0

It's probably not possible IIRC.

Bitcoin Core creates a lock file that is only deleted once the program exits. If Bitcoin Core detects such a file, the instance will not run. Accessing Blockchain from two different places would result in a corruption (same scenario as how Blockchain gets corrupted if anti viruses attempts to scan it).

Why would you do this?

Most reasons should be easily solvable by using an RPC call instead of a second deamon, isn't it?

I am trying to understand, for example, whether somebody could run 10 bitcoin full nodes only using one single copy of the blockchain thus saving on storage costs.

More specifically, I want to understand whether it is possible to prevent this behavior if it is already possible.

Now you are asking the correct question. The answer is, yes its possible to fake e.g. 10 full nodes while only providing the resources (or only slightly more) of a single node. The 9 fake nodes would run custom software (not core!) that would forward the requests to the single full node. In theory this full node can be any other on the network that is available, so you could do this without running a single node.

The idea to proof that you run a full node and thus get rewarded for doing so has been brought up several times. I have not seen a good solution yet. I would applaud a solution as the number of nodes decreases and the costs of running one increase.

There is another thread from 2011 which is about Multiple bitcoind on one machine. Maybe you can find some more ideas there.
https://bitcointalk.org/index.php?topic=34769.0

[KingZee]

Since your issue is simply connecting one instance of the blockchain to multiple servers, my answer on this other post will be relevant to you :

I have quick question on how we can use two bitcoin node in load balancing mode. Is there any way, if one node goes down another can take care of all request.

Any inputs are appreciated, we dont want to share dat file to both servers.

I guess you already have a NAS setup? Your servers running the nodes also need to be able to mount a NFS volume. Go to your bitcoin.conf and set the datadir to your newly mounted volume.

https://www.reddit.com/r/btc/comments/4r48oa/running_a_node_with_the_database_on_a/d4yolwm/

This link has a lot of information that's going to be useful to you.

You can download the blockchain and keep it on a NAS, then set the directory in your bitcoin.conf to that drive. The technicalities are detailed very well in the reddit link so check it out.