Migrate to Hyper-Converged Database (HCD)
The migration process includes exporting data from its original location, uploading or importing your data to your new Hyper-Converged Database (HCD) cluster, and then updating your applications to connect to your new databases.
Migrate your data
When moving from another platform to HCD, you can migrate your data from your existing cluster to a new cluster, or you can perform an in-place upgrade to HCD without moving your data.
Zero Downtime Migration (ZDM)
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DataStax strongly recommends using the ZDM tools for data migrations whenever possible. For supported migration paths, see Cluster compatibility for Zero Downtime Migration. |
The ZDM tools provide the safest upgrade approach with blue-green deployment capabilities that eliminate time pressure and ensure optimal availability and operational safety.
Here’s how the ZDM process works:
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Set up your new, empty HCD cluster separate from your existing cluster.
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Use the ZDM tools to orchestrate live reads and writes while you use a data migrations tool to replicate your data on the new cluster.
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Validate the data on the new cluster and simulate production workloads before permanently switching your traffic to the new cluster.
Your original cluster remains running during the entire process, allowing you to seamlessly stop the migration at any point up until the last phase when you stop sending traffic to the original cluster.
Benefits of a ZDM approach
Using ZDM tooling to do a blue-green migration of your cluster to HCD creates a unique window to fix critical configuration settings:
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Reduce vnodes (
num_tokens) to 16 or lower. -
Change the partitioner to
Murmur3Partitioner. -
Remove
COMPACT STORAGEfrom tables. -
Apply
frozento collections and UDTs (where applicable). -
Re-order columns in the
PRIMARY KEY(where applicable). -
Change the
data_dirvolume from JBOD to a striped LVM. -
Change the
data_dirfilesystem toxfs, with 4kb block size, 4kb stripe width, and 64kb stripe unit.It also presents the opportunity to correctly configure internode (server-to-server) encryption and security with less effort and risk.
To learn more and get started on your zero downtime migration to HCD, see DataStax migration tools.
In-place upgrade
In-place upgrades replace the database platform on your current cluster with HCD without moving your data.
This option is available only for specific migration paths, and DataStax recommends that you use this option only if your existing cluster doesn’t support Zero Downtime Migration (ZDM).
In-place upgrades have the following limitations:
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Requires downtime during the upgrade process
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Requires you to systematically reconfigure your cluster before, during, and after the upgrade
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Carries a higher risk of unavailability and downtime
For in-place upgrade instructions, see the following:
Migrate your code
After migrating your data to HCD, your applications can connect exclusively to your HCD databases.
Aside from the database connection, your code might not require any other changes if you already use a compatible driver and CQL statements. However, you might consider migrating your code to the Data API, which provides programmatic access to collections and tables in your vector databases, including vector search and hybrid search capabilities.
