Geth logs

A Geth node continually reports messages to the console allowing users to monitor Geth's current status in real-time. The logs indicate when Geth is running normally and indicates when some attention is required. However, reading these logs can be difficult for new users. This page will help to interpret the log messages to better understand what Geth is doing.

Note that there are a large number of log messages covering a wide range of possible scenarios for a Geth node. This page will only address a subset of commonly seen messages. For more, see the Geth GitHub, Discord or search on ethereum.stackexchange. Log messages are usually sufficiently self-describing that they do not require additional explanation.

Configuring log messages

Log messages are displayed to the console by default. The messages can be tuned to be more or less detailed by passing --verbosity and a value between 0 and 5 to Geth at startup:

0 = silent (no log messages)
1 = error (error messages only)
2 = warn (error messages and warnings only)
3 = info (error messages, warnings and normal activity logs)
4 = debug (all info plus additional messages for debugging)
5 = detail (all info plus detailed debugging messages)

The default is --verbosity 3.

Log messages can also be redirected so they are saved to a text file instead of being displayed in the console. In Linux the syntax >> <path> 2>&1 redirects both stdout and stderr messages to <path>. For example:

# saves detailed logs to path/eth.log
geth --verbosity 5 >> /path/eth.log 2>&1

Startup

When Geth starts up it immediately reports a fairly long page of configuration details and status reports that allow the user to confirm Geth is on the right network and operating in its intended modes. The basic structure of a log message is as follows:

MESSAGE_TYPE [MONTH-DAY][TIME] MESSAGE VALUE

Where MESSAGE_TYPE can be INFO, WARN, ERROR or DEBUG. These tags categorize log messages according to their purpose. INFO messages inform the user about Geth's current configuration and status. WARN messages are for alerting the user to details that affect the way Geth is running. ERROR messages are for alerting the user to problems. DEBUG is for messages that are relevant to troubleshooting or for developers working on Geth.

The messages displayed on startup break down as follows:

The logs above show the user that the node is connecting to Ethereum Mainnet and some low level configuration details. The cache size is bumped to the Mainnet default (4096). The maximum peer count is the highest number of peers this node is allowed to connect to and can be used to control the bandwidth requirements of the node. Logs relating to ethash are out of date since Ethereum moved to proof-of-stake based consensus and can safely be ignored.

The above block of messages are related to past Ethereum hard forks. The names are the names of the hard forks and the numbers are the blocks at which the hard fork occurs. This means that blocks with numbers that exceed these values have the configuration required by that hard fork. The specification of each hard fork is available at the provided links (and more information is available on ethereum.org). The message Consensus: Beacon (proof-of-stake), merged from Ethash (proof-of-work) indicates that the node requires a Beacon node to follow the canonical chain - Geth cannot participate in consensus on its own.

The messages above relate to The Merge. The Merge was Ethereum's transition from proof-of-work to proof-of-stake based consensus. In Geth, The Merge came in the form of the Paris hard fork which was triggered at a terminal total difficulty of 58750000000000000000000 instead of a preconfigured block number like previous hard forks. The hard fork specification is linked in the log message. The message network known to be merged: true indicates that the node is following a chain that has passed the terminal total difficulty and undergone the Paris hard fork. Since September 15 2022 this will always be true for nodes on Ethereum Mainnet (and the merged testnets Sepolia and Goerli). The warning Engine API enabled informs the user that Geth is exposing the set of API methods required for communication with a consensus client.

The logs above relate to Geth starting up its peer-to-peer components and seeking other nodes to connect to. The long address reported to Started P2P networking is the nodes own enode address. The IPC Endpoint is the location of the node's IPC file that can be used to connect a Javascript console. There is a log message confirming that a JWT secret was generated and reporting its path. This is required to authenticate communication between Geth and the consensus client. There are also messages here reporting on the HTTP server that can be used to send requests to Geth. There should be two HTTP servers - one for interacting with Geth (defaults to localhost:8545) and one for communication with the consensus client (defaults to localhost:8551).

Syncing

The default for Geth is to sync in snap mode. This requires a block header to be provided to Geth by the consensus client. The header is then used as a target to sync to. Geth requests block headers from its peers that are parents of the target until there is a continuous chain of sequential headers of sufficient length. Then, Geth requests block bodies and receipts for each header and simultaneously starts downloading state data. This state data is stored in the form of a Patricia Merkle Trie. Only the leaves of the trie are downloaded, the full trie structure is then locally regenerated from the leaves up. Meanwhile, the blockchain continues to progress and the target header is updated. This means some of the regenerated state data need to be updated. This is known as healing.

Assuming Geth has a synced consensus client and some peers it will start importing headers, block bodies and receipts. The log messages for data downloading look as follows:

For state sync, Geth reports when the state heal is in progress. This can take a long time. The log message includes values for the number of accounts, slots, codes and nodes that were downloaded in the current healing phase, and the pending field is the number of state entries waiting to be downloaded. The pending value is not necessarily the number of state entries remaining until the healing is finished. As the blockchain progresses the state trie is updated and therefore the data that need to be downloaded to heal the trie can increase as well as decrease over time. Ultimately, the state should heal faster than the blockchain progresses so the node can get in sync. When the state healing is finished there is a post-sync snapshot generation phase. The node is not in sync until the state healing phase is over. If the node is still regularly reporting State heal in progress it is not yet in sync - the state healing is still ongoing.

The sync can be confirmed using eth.syncing - it will return false if the node is in sync. If eth.syncing returns anything other than false it has not finished syncing. Generally, if syncing is still ongoing, eth.syncing will return block info that looks as follows:

> eth.syncing
{
  currentBlock: 15285946,
  healedBytecodeBytes: 991164713,
  healedBytecodes: 130880,
  healedTrienodeBytes: 489298493475,
  healedTrienodes: 1752917331,
  healingBytecode: 0,
  healingTrienodes: 1745,
  highestBlock: 16345003,
  startingBlock: 12218525,
  syncedAccountBytes: 391561544809,
  syncedAccounts: 136498212,
  syncedBytecodeBytes: 2414143936,
  syncedBytecodes: 420599,
  syncedStorage: 496503178,
  syncedStorageBytes: 103368240246
}

There are other log messages that are commonly seen during syncing. For example:

WARN [09-28|11:06:01.363] Snapshot extension registration failed

This warning is nothing to worry about - it is reporting a configuration mismatch between the node and a peer. It does not mean syncing is stalling or failing, it simply results in the peer being dropped and replaced.

# consensus client has identified a new head to use as a sync target - account for this in state sync
INFO [10-03|15:34:01.336] Forkchoice requested sync to new head    number=15,670,037 hash=84d4ec..4c0e2b

The message above indicates that the fork choice algorithm, which is run by the consensus client, has identified a new target Geth should sync up to. This redirects the sync to prevent syncing to an outdated target and is a natural part of syncing a live blockchain.

Transaction logs

Transactions submitted over local IPC, Websockets or HTTP connections are reported in the console logs. For example, a simple ETH transaction appears in the console logs as follows:

INFO [09-06|01:31:59.910] Submitted transaction             hash=0x2893b70483bf1791b550e5a93763058b0abf7c6d9e6201e07212dbc64d4764532 from: 0xFB48587362536C606d6e89f717Fsd229673246e6 nonce: 43 recipient: 0x7C60662d63536e89f717F9673sd22246F6eB4858 value: 100,000,000,000,000,000

Other user actions have similar log messages that are displayed to the console.

Common warnings

There are many warnings that can be emitted by Geth as part of its normal operation. However, some are asked about especially frequently on the Geth GitHub and Discord channel.

WARN [10-03|18:00:40.413] Unexpected trienode heal packet          peer=9f0e8fbf         reqid=6,915,308,639,612,522,441

The above is often seen and misinterpreted as a problem with snap sync. In reality, it indicates a request timeout that may be because I/O speed is low. It is usually not an issue, but if this message is seen very often over prolonged periods of time it might be rooted in a local connectivity or hardware issue.

WARN [10-03|13:10:26.441] Post-merge network, but no beacon client seen. Please launch one to follow the chain!

The above message is emitted when Geth is run without a consensus client on a post-merge proof-of-stake network. Since Ethereum moved to proof-of-stake Geth alone is not enough to follow the chain because the consensus logic is now implemented by a separate piece of software called a consensus client. This log message is displayed when the consensus client is missing. Read more about this on our consensus clients page.

WARN [10-03 |13:10:26.499] Beacon client online, but never received consensus updates. Please ensure your beacon client is operational to follow the chain!

The message above indicates that a consensus client is present but not working correctly. The most likely reason for this is that the client is not yet in sync. Waiting for the consensus client to sync should solve the issue.

WARN [10-03 | 13:15:56.543] Dropping unsynced node during sync    id = e2fdc0d92d70953 conn = ...

This message indicates that a peer is being dropped because it is not fully synced. This is normal - the necessary data will be requested from an alternative peer instead.

Summary

There are a wide range of log messages that are emitted while Geth is running. The level of detail in the logs can be configured using the verbosity flag at startup. This page has outlined some of the common messages users can expect to see when Geth is run with default verbosity, without attempting to be comprehensive. For more, please see the Geth GitHub and Discord.