Database migration between Cassandra servers

This section describes the way to transfer data between the Azure Managed Instances of Apache Cassandra. This is done with the help of “nodetool” and “sstableloader” commands via the Azure CLI using the steps outlined below. For more information on the DBA commands for this instance, please visit https://learn.microsoft.com/en-us/azure/maaged-instance-apache-cassandra/dba-commands. Ensure that your automation identity has the necessary permission to run azcopy and az cli.

1. The first step involves creating a snapshot of the data. This is done with:

# Create a snapshot

az managed-cassandra cluster invoke-command \

  --resource-group <resource-group> \

  --cluster-name <cluster-name> \

  --host <host-ip> \

  --command-name nodetool \

  --arguments "snapshot <keyspace> -t <snapshot-name>"

# Download the snapshot files using azcopy

azcopy copy "https://<storage-account>.blob.core.windows.net/<container>/<path-to-snapshot>/*" "<local-directory>"

2. The second step involves uploading the snapshot to another instance. This is done with:

# Upload the snapshot files using azcopy

azcopy copy "<local-directory>/*" "https://<storage-account>.blob.core.windows.net/<container>/<path-to-upload>"

# Load the data using sstableloader

az managed-cassandra cluster invoke-command \

  --resource-group <resource-group> \

  --cluster-name <cluster-name> \

  --host <host-ip> \

  --command-name sstableloader \

  --arguments "-d <data-directory> <keyspace> <table>"

3. Finally, test that the data are similar.

Data Backup/Restore or Migration are usually considered last resort as most resources in Azure allow continuous replication across paired servers. But when they become inevitable, these steps make the task easier.