How to resync Geth

A common reason for Geth to fail can be an unexpected shutdown of a validator machine. Geth uses RAM for temporary memory and during a graceful shutdown some important information will be written to disk. However, during an unexpected shutdown, there isn't time to write to disk (e.g. due to a sudden loss of power) so important data is lost. This loss of data leads to a corruption of the chaindata folder, requiring a resync.

• File Locations

• Steps (If the ancient folder exists)

• Steps (If the ancient folder does not exist)

File Locations

• Standard location of the chaindata folder.

  Copy

  /var/lib/goethereum/geth/chaindata/

• Standard location of the ancient folder.

  Copy

  /var/lib/goethereum/geth/chaindata/ancient

Steps (If the ancient folder exists)

Good news! The required resync can be made much faster than a full resync simply by keeping the ancient folder. The ancient folder contains files that are not corrupted during an unexpected shutdown.

1. Stop Geth.

2. Move the ancient folder.

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   sudo mv /var/lib/goethereum/geth/chaindata/ancient /var/lib/goethereum/geth/

3. Delete the chaindata directory and recreate it.

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   sudo rm -rf /var/lib/goethereum/geth/chaindata
   sudo mkdir /var/lib/goethereum/geth/chaindata

4. Move the ancient folder back to the now empty chaindata directory.

   Copy

   sudo mv /var/lib/goethereum/geth/ancient /var/lib/goethereum/geth/chaindata

5. Change the ownership of the chaindata directory to the Geth user.

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   sudo chown -R goeth:goeth /var/lib/goethereum/geth/chaindata
   sudo chmod 755 /var/lib/goethereum/geth/chaindata
   sudo chmod 755 /var/lib/goethereum/geth/chaindata/ancient

6. Start Geth.

Congratulations! You've successfully started a Geth resync 🥳

Steps (If the ancient folder does not exist)

If the ancient folder does not exist, that's not a problem. It just means you will need to resync Geth from scratch, which will take a bit longer.

1. Stop Geth.

2. Delete the chaindata directory and recreate it.

   Copy

   sudo rm -rf /var/lib/goethereum/geth/chaindata
   sudo mkdir /var/lib/goethereum/geth/chaindata

3. Confirm the ownership and permissions for the chaindata directory are set to the Geth user.

   Copy

   sudo chown -R goeth:goeth /var/lib/goethereum/geth/chaindata
   sudo chmod 755 /var/lib/goethereum/geth/chaindata

4. Start Geth.

Congratulations! You've successfully started a Geth resync 🥳