FAQ

I noticed my peercount slowly decrease, and now it is at 0. Restarting doesn't get any peers.

Check and sync your clock with ntp. Example sudo ntpdate -s time.nist.gov

If this doesn't help, please review the Connecting To the Network Wiki page.

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I would like to run multiple geth instances but got the error "Fatal: blockchain db err: resource temporarily unavailable".

Geth uses a datadir to store the blockchain, accounts and some additional information. This directory cannot be shared between running instances. If you would like to run multiple instances follow these instructions.

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I sent a transaction, but it's forever 'pending'. I see no errors, but geth doesn't seem to be processing the transaction.

Check your transaction's nonce value. If a transaction with a nonce is submitted with a "too high" nonce value, geth will hold the transaction in memory and wait until it receives a transaction with a correct nonce to insert before yours. Nodes can receive transactions asynchronously, so there is no way to check if a nonce is (or will be) missing completely.

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What is the difference between chain id, chain identity, and network id?

• chain id is used by the chain configuration for signing replay-protected (see EIP155) transactions. It is configured in the "Diehard" upgrade fork.
• chain identity is a local value, and is not a part of the p2p or blockchain protocols, per se. With default values "mainnet" and "morden", it can be used as an argument to specify a custom chain. When doing so, the configuration file JSON key "identity" must match the containing subdirectory (/datadir/customnet/chain.json) to ensure your configurations are in proper order.
• network id is used in the p2p protocol to identify valid peers on a given network. Mainnet network id is 1, Morden is 2, and your private net can be any positive integer (although best not 1 or 2, to avoid trying unuseful peers).