Multiple bitcoind on one machine

[wumpus]

The core development team is actively working against this goal

That's simply not true. The recent WalletDB refactoring made it possible to run multiple wallets in one process with only a few changes.

[1715146475]

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[1715146475]

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[payb.tc]

just one reason of many, i'd say.

Do share the other reasons as they come to you.

I don't see how what you've said so far is a problem.

Don't take me the wrong way, I am genuinely interested in where the existing functionality fails to suffice

okay well here's one more reason i can think of... let's say there are TWO types of ways a site can use bitcoin:

1) the kind of site where new temporary addresses are constantly being generated for incoming payments, eg. btcflip.com
2) the kind of site where there is only ever 1 permanent address generated per customer (I think tradehill might be starting to do this).

for a site in category 1, it's wallet.dat is going to be constantly growing day by day, hour by hour, and will probably need to be replaced with a fresh one periodically, so that the site isn't running off a 100mb wallet file. These are just 'temporary' payment addresses, 99% of which might not have ever even had payments sent to them.

the site in category 2 might have 1000 customers, but it's wallet.dat could have as little as 1000 addresses and not need periodically replacing. Indeed for this kind of site replacing the wallet would be a bad thing, as each customer has been given his 'personal' address for that site.

now you tell me, what would be the best way to run these two types of sites on the same server?

[payb.tc]

I don't see how what you've said so far is a problem.

no sub-accounts?

the documentation basically recommends that accounts should be used to organise customers, say alice and bob.

so under normal circumstances your wallet file might have:

[alice]=>0.5
[bob]=>1.3

but let's say you have a second website which has customers alice and jane, but the catch is, it's NOT THE SAME ALICE

[alice]=>5000
[jane]=>20

so the only way to get around this is to add prefices to account names to designate what site they're customers of:

[a-alice]=>0.5
[a-bob]=>1.3
[b-alice]=>5000
[b-jane]=>20

would be much better organised with sub accounts:

[site a]=>1.8,
(
   [alice]=>0.5
   [bob]=>1.3
)
[site b]=>5020,
(
   [alice]=>5000
   [jane]=>20
)


actually, even if it was the same alice, you wouldn't want her to log in to site a or b and see her balance as 5000.5  ...those balances should remain separate.

[jfreak53]

We run 12 to 15 per server depending on the load of each.  Not so much for Ram, each one takes about 150MB of ram total per user, but we have it limited also.  But more for the IO, it really uses a lot and more just seems to bog down the server we have noticed.

We used the same basic technique in the second reply to this thread.

[2112]

But more for the IO, it really uses a lot and more just seems to bog down the server we have noticed.

If you know how to recompile you can try disabling memory mapping in the calls to db->open. The flag is DB_NOMMAP. It could slightly improve the disk cache hit ratio and it will greatly improve TLB hit ratio, especially on the virtualized servers.

[jfreak53]

We will give that a try since we compile our own anyways, I will shoot that over and see if it helps some, thanks.

Since we're on the subject, any idea where to look to lower memory consumption off the top of your head?

[2112]

Since we're on the subject, any idea where to look to lower memory consumption off the top of your head?

For the managed hosting environment (multiple bitcoind each with its own wallet, but reasonably good security) I would work as follows:

1) create a separate DBENV for the blkindex.dat
2) convert stdio.h access to blkNNNN.dat into DB access to additional named databases inside blkindex.dat, which already supports multiple databases, take care that block insertion is idempotent
3) convert the new environment from (1) from direct calls into RPC calls
4) run berkeley_db_svc RPC server serving a single copy of blockchain inside blkindex.dat for all the client bitcoin-daemons, each of which is only managing its own wallet in a separate (original) DBENV

This modification will give you best bang for your development buck in the reasonably secure managed hosting environment.

[jfreak53]

Very nice idea 2112, I'll have our Devs look into it for integration.

[tolazy]

The overhead can be stupendous though.

You mean as in ram usage or are you talking about something else?

i was able to get 2 running successfully for a while on a test server.

I wonder what the record is for the most amount of bitcoind instances running together successfully... anyone running 3 or more?

how did you manage to do that?
can you give me the startup command line/config pls.

[2112]

how did you manage to do that?
can you give me the startup command line/config pls.

This thread is only of historical relevance. It pertains to the old version that used BerkelyDB for everything. Current version uses a mixture of BerkeleyDB and LevelDB, so it doesn't apply.