Hyper-Converged Database (HCD) Frequently Asked Questions (FAQs)

You can provision and deploy an HCD cluster using the Mission Control UI, manually using the CLI, or with Docker to explore standalone container development in a local, non-prod environment. DataStax recommends using Mission Control to manage your clusters in production environments. For more information, see Install HCD.

The Docker image can be deployed as a standalone container for development environments.

HCD runs on premises and in the cloud, and uses Mission Control for provisioning and management. HCD is intended for companies that must manage their database resources on cloud providers, such as AWS, Google Cloud, and Microsoft Azure.

Astra DB allows you to create databases in minutes, with reduced complexity, fewer operational concerns, and an approachable entry point for developing your applications. Astra DB is a true database-as-a-service (DBaaS) offering that provides simplified database management with flexible pricing.

HCD is the future of self-managed data, designed for modern data centers and Hyper-Converged Infrastructure (HCI) to support data workloads and AI systems at scale. It supports powerful on-premises enterprise data systems built to enable AI data and is ideal for enterprise operators and architects who want to take advantage of data center modernization investments to reduce operating costs and operational overhead.

HCD runs on premises and in the cloud, and uses Mission Control for provisioning and management. HCD is intended for companies that must manage their database resources on cloud providers, such as AWS, Google Cloud, and Microsoft Azure.

While you can run DSE on premises and in the cloud, HCD allows you to manage your database resources with modern architecture and a cloud-native approach.

DSE includes Advanced Workloads (DSE Search, Analytics, and Graph), which are not currently available in HCD. HCD will add more features and capabilities over time.

The following DataStax drivers are compatible with HCD:

There is no practical limit to the number of bytes an HCD database can store.

SAI is a highly-scalable, globally-distributed index for Apache Cassandra® that is available for HCD databases.

Explore this deep dive on Storage Attached Indexing.

If you need to make firewall exceptions, HCD uses the following ports:

Yes, you can alter the namespace or keyspace name. You can also create a new namespace or keyspace with a different name.

This is the common error:

Invalid Request: Error from server: code=2200
[Invalid query] message="table TABLE_NAME does not exist"

When you create a table, the table name, keyspace name, or column name is case-sensitive. You can access case-sensitive characters using double quotes.

For example, see the SELECT statement below:

The NoSQL term originally referred to a new generation of databases that shunned SQL for other interfaces. The term NoSQL has recently become a catch-all term for post-relational "not-only SQL" databases that use a method of storage different from a relational, or SQL, database.

HCD is a distributed and highly available database that uses peer-to-peer communication. Data modeling in HCD is similar to relational databases while differing in key areas to provide blazing fast interaction. Relational databases use joins between tables for relationships. HCD uses denormalization to achieve more robust querying.

The Capacity Planning Guide provides recommendations for choosing hardware including number of CPUs, amount of RAM and type of disks appropriate for the workload and environment.

Mission Control is the next generation operations platform for deploying, managing, and maintaining HCD, DataStax Enterprise (DSE), and Cassandra clusters. It provides a web-based interface that simplifies management and operation of HCD clusters.

HCD architecture allows any authorized user to connect to any node in any datacenter and access data using the Cassandra Query Language (CQL 3.4.5 protocol v5). For ease of use, CQL uses a similar syntax to SQL. The most basic way to interact with HCD is using the CQL shell, cqlsh. Using cqlsh, you can create keyspaces and tables, insert records and query tables, and much more. Other ways to interact with HCD are:

HCD provides several solutions for migrating data from other databases: DataStax Bulk Loader (DSBulk) is an open-source utility for loading or unloading data in CSV or JSON format into and out of HCD databases.

DataStax is committed to data privacy and security. This commitment includes robust security measures and compliance standards, such as HIPAA, SOC2 Type 2, and ISO 27001.

For more information, see the DataStax Trust Center.

HCD extends eventual consistency with tunable consistency to vary the consistency of reads and writes. For more information, see How are consistent read and write operations handled?.

HCD does not use RDBMS ACID transactions; instead HCD offers atomic, isolated, and durable transactions with eventual/tunable consistency. For more information, see How do Hyper-Converged Database (HCD) transactions differ from RDBMS transactions?.

For information about when and why to use lightweight transactions see How do I accomplish lightweight transactions with linearizable consistency?.

Use tracing to discover what the consistency level is set to, and how it affects performance. For more information, see How do I discover consistency level performance?.

Consistency levels in HCD can be configured to manage availability versus data accuracy. For more information, see How is the consistency level configured?.

Serial consistency levels control lightweight transaction (LWT) isolation. For more information, see How is the serial consistency level configured?.

A coordinator node can send three types of read requests to a replica. For more information, see How are read requests accomplished?.

The write consistency level determines how many replica nodes must respond with a success acknowledgment in order for the write to be considered successful. For more information, see How are write requests accomplished?.

You can contact DataStax Support or search the knowledge base for assistance.

If you identify an alert or incident, you can submit a support ticket for help. Go to Support Onboarding to learn how to submit a ticket.