How do I copy the database from one node over to another node?
Introduction
When we deploy new nodes or have to completely redo one from the ground up we could make a copy of an existing database and have a copy of that be transferred to our new node to mitigate all the time and server resources it would take to sync the database from epoch 0.
Step 1 - Stop our source node
Let's start by stopping our node from where we will make source the database
sudo systemctl stop cnode.serviceStep 2 - Move over to Database and do some preparation
We need to change over to our db folder under our cardano node
cd db #Or wherever you have chosen to store your files and folders
lsYou should see something like this:
OUTPUT:
immutable ledger lock protocolMagicId shelley_trans_epoch volatileStep 3 - Remove the contents of the ledger directory
rm -rf ledger/* #Remove everything in the ledger dir using the options of -rf (recursively, force)Step 4 - Restart the node
sudo systemctl start cnode.serviceLet the database sync again before we stop the node again.
How do we know when the database is synced on the blockchain? To answer that you can follow the steps by Damien Ostrelich of EDEN pools in his YouTube tutorial:
Or you can copy paste his instructions here:
cd ../logs
tail -f node0.jsonThe output shows the db syncing in real time.
But we want to filter the output to show us only those lines that cnoptain the "contents" parameter
tail -f node0.json | grep "contents"The lines on output will now only show those lines that contain the "contents" parameter (usually highlighted in red). The contents parameter is an indicator of the amount of db synced and we need to wait till the subsequent indicator after the "contents" word in the line reaches 100 (100%). See video above to see this in real time.
Step 5 - Stop the node (again) and take a snapshot
Once the node sync contents are 100% we stop the node
sudo systemctl stop cnode.serviceCompress a copy of your database (this will take some time)
cd ..
tar -czvf db_snapshot.tar.gz db/Once the snapshot (the compressed file completed) we restart the node
sudo systemctl start cnode.serviceStep 6 - Copy the compressed database over to your new node
This step can be done to your liking. Either by transferring using an app like FileZilla to download the file and reupload to your new server. Or, you can do the transfer from the command line and login to the new server using ssh and do a direct server to server transfer. We leave this step up to you.
Step 7 - Stop your destination node
sudo systemctl disable cnode.service
sudo systemctl stop cnode.serviceStep 8 - Rebuild node software as if you are updating the node upgrade
This is the common procedure of upgrading your node software and binaries. You do this as you would any other normal upgrade and instructions on this are skipped since this is covered multiple times in answers on CardanoFAQ.
Step 9 - Replace database after Cardano node is updated and upgraded
Decompress (extract) the db_database.tar.gz file you uploaded into the directory holding the db directory. First we backup the existing database in case we need to roll back for whatever reason.
cp -r db/ db-backup/Remove the database
rm -r dbExtract the database tar file
tar -xzvf db_snapshot.tar.gzThis will recreate the db folder with all of its contents
Step 10 - Restart the cnode service
systemctl enable cnode.service
systemctl start cnode.service
systemctl status cnode.serviceStep 11 - Check to see the database is syncing to the network
Here we can open our gLiveView utility and just check that it is syncing and working again.
That should be it!
Links used in this answer:
Damien Ostrelich's YouTube tutorial on this issue: https://youtu.be/4CxYezEvFnY
This answer was published 02 Jan 2021
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