Chaindata Change


CN Node Migration STEP

Create new disk

  1. Preparing new disk (3,500GB disk) or creating new path on the current disk (It must have 3,500GB available.)

💡 Assuming that the new path is `/var/kcnd2`

Option 1 - New disk (more than 2500GB)

  1. Attach the disk to EC2 and run the command below

$ lsblk
nvme2n1       259:0    0  3500G  0 disk **# New Disk**
nvme1n1       259:0    0  4000G  0 disk /var/kcnd
nvme0n1       259:2    0    8G  0 disk
├─nvme0n1p1   259:3    0    8G  0 part /
└─nvme0n1p128 259:4    0    1M  0 part
  1. Mount it following the process below

$ sudo e2fsck -f /dev/nvme2n1
$ sudo mkfs -t ext4 /dev/nvme2n1
$ sudo mkdir /var/kcnd2
$ sudo mount /dev/nvme2n1 /var/kcnd2
$ sudo mkdir /var/kcnd2/data
$ sudo mkdir /var/kcnd2/log
  1. Create New Folder

$ sudo mkdir /var/kcnd2/data
$ sudo mkdir /var/kcnd2/log

Download the latest chaindata

Download Chain Data to the data of the new Klaytn Data DIR. (You can check the details on Chain Data in

  1. Download with the following command

# (Option 1: recommended) curl 
$ curl -o klaytn-cypress-chaindata-2021???????????.tar.gz ""

# (Option 2) aws s3 command
$ aws s3 cp s3://klaytn-chaindata/cypress/klaytn-cypress-chaindata-2021???????????.tar.gz klaytn-cypress-chaindata-20211113011111.tar.gz 

# (Option 3) axel (need to install axel)
sudo amazon-linux-extras install epel -y
sudo yum install axel pigz
$ axel -n8
  1. Decompress

# (Option 1: recommended) tar
$ tar -xvf klaytn-cypress-chaindata-2021???????????.tar.gz

# (Option 2) pigz (need to isntall pigz)
$ tar -I pigz -xvf klaytn-cypress-chaindata-2021???????????.tar.gz

Configure DATA_DIR & LOG_DIR

Option 1 - Swap the old & new path


  1. Stop klaytn daemon process before swap

    1. IMPORTANT Remove CN node in Klaytn council if the node type is CN

    💡 You can get packages for EN in the Startup the CN.

  2. Swap the old and new path

    1. New Disk

      umount /var/kcnd # old path
      umount /var/kcnd2 # new path
      mount /dev/nvme2n1 /var/kcnd

    💡 These commands should be executed with the appropriate privileges.

    1. Current Disk

      sudo mv /var/kcnd /var/kcnd_old # old_path
      sudo mv /var/kcnd2 /var/kcnd # new path
  3. (Optional) Delete the old path if it is not required anymore

Option 2 - Update DATA_DIR & LOG_DIR in klaytn config file

  1. Klaytn DIR Path Change

    • Option 1 - New disk

      • Change fstab value from old disk to new disk

    • Option 2 - Current disk

      • change the DIR Path from kcnd.conf

Restart Process(or Reboot Instance)

💡 If reboot is required to add an additional disk, reboot the instance.

  1. IMPORTANT Remove CN node in Klaytn council if the node type is CN

  2. Restart process or reboot instance

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