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.
/var/lib/goethereum/geth/chaindata/
Standard location of the ancient folder.
/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.
sudo mv /var/lib/goethereum/geth/chaindata/ancient /var/lib/goethereum/geth/
3.Delete the chaindata directory and recreate it.
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.
sudo mv /var/lib/goethereum/geth/ancient /var/lib/goethereum/geth/chaindata
5.Change the ownership of the chaindata directory to the Geth user.
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.
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.
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 🥳

Last modified 3mo ago