Why Migrate from Netezza to Snowflake?

Netezza, commonly known as IBM Netezza, is a legacy on-premises data warehouse. It is a combined hardware and software design that utilizes Massive Parallel Processing(MPP) architecture, distributing data and processing across multiple nodes. Modern technologies require unlimited concurrency, higher performance, and the ability to handle a large volume of data. Netezza was robust in its time, but now struggles to meet the current business needs. This disadvantage of Netezza is considered an advantage to cloud platforms like Snowflake. With its cloud-based architecture, Snowflake boosts companies' efficiency and reduces costs.

By moving your data to the cloud, you could gain the following advantages.

• Centralized storage and Elasticity: Snowflake can separate data storage from compute functionality. All data-structured, semi-structured, and unstructured data is stored in one location in a columnar format. It can handle a sudden increase in the data load without affecting the performance. This feature makes it elastic. 
• Cost-efficient: It eliminates the need for physical hardware management and maintenance, thereby reducing the operational costs to the company, unlike Netezza. With less complexity, its resource usage is optimized, and fewer people are needed. It operates on a pay-as-you-go pricing model, which means we only pay for the resources we use.
• Scalability: Netezza requires scaling of hardware resources, whereas  Snowflake allows independent scaling through separate storage. It helps the business to scale up when there is more load and scale down when there is less load. 
• Faster Data access and query performance: Compared to Netezza, Snowflake provides faster data access due to its elastic nature. Data retrieval is faster during a heavy load because column-based storage is used. This feature makes it more efficient.
• Advanced analytics and real-time processing:  Snowflake’s architecture excels in handling advanced analytics, real-time data processing, and machine learning. This is one of the major features that makes them stand out from the traditional on-premises warehouse.
• Data Recovery: Data retrieval is significantly faster in a cloud-based architecture, and it offers enhanced disaster recovery measures.

Overall, Snowflake is a flexible, affordable, and faster data warehouse that improves performance and thereby aligns with the organization's goals. Because of its cloud-native architecture, it streamlines the data. This gives faster performance and agility compared to physical data warehouses like Netezza. 

Things to Consider Before Migrating from Netezza to Snowflake

Netezza to Snowflake migration requires good planning and execution. Some of the key considerations that can maximise the benefits are  

• Architectural changes: Netezza’s on-premises architecture differs from Snowflake’s cloud architecture. Utmost care should be taken when storing data in columnar format.
• Complexity: The complexity of migration depends on the data size and the Netezza environment. 
• SQL conversions: This is one of the most challenging aspects in converting data from Netezza to Snowflake, as they both have different SQL syntax. Date, time functions, string manipulations, and stored procedures vary significantly between Netezza and Snowflake. Netezza is aligned to NZPL SQL, supports arrays and complex data types, whereas Snowflake uses standard ANSI SQL for cloud and semi-structured data. Automated code conversion tools should be considered for this scenario, and manual rewriting and refactoring of SQL scripts and queries are required. Proper mapping of data types needs to be done from Netezza to Snowflake.
• Security measures and compliance: Snowflake uses Role-based Access Control (RBAC), so carefully map existing users, roles, and permissions in Snowflake‘s cloud model.
• Timeline considerations and budget: Migration usually takes from 12 weeks to a year, depending on the data volume and complexity, so determine the timelines and adjust the budget by using a pay-as-you-go pricing model.

How to Migrate from Netezza to Snowflake (8-step process)

For a successful Netezza to Snowflake migration, the steps are described below

1. Planning and Analyzing the environment: Make a clear and detailed plan for the migration with proper documentation. A complete check needs to be done on the Netezza setup. Create a list of tables, databases, users, user-defined functions, procedures, roles, and applications that need to be migrated. Document all the dependencies and data flows such that nothing is missed during migration.
2. Choose a migration plan: Choosing a migration plan depends on factors like data volume and available tools. Either phased migration (moving in stages) or lift-and-shift (moving all the required things at once) migration can be used.
3. Create a Snowflake database: Set up tables, accounts, schemas, roles, and users in Snowflake. The database logic needs to be converted from Netezza’s NZPLSQL to Snowflake’s ANSI SQL through stored procedures. Using RBAC control, user and service-level based permissions. 
4. Convert Schema and SQL code: Start by moving the data model obtained by Netezza’s DDL scripts.  Convert Netezza’s specific data types to their Snowflake equivalent, like INTERVAL datatypes in Netezza are not available, and their equivalent N/A data type should be mentioned in Snowflake. This step will ensure that all the database objects are created successfully in Snowflake. Complex logic in stored procedures needs to be manually written and reviewed. Ensure that all the queries and procedures work as intended in the Snowflake database. SQL queries need to be modified according to the Snowflake database; otherwise, it leads to errors.
5. Transfer the data and load it in Snowflake: Existing data from Netezza needs to be moved. JDBC drivers can be used directly to load the data into Snowflake. It can be done manually or through migration tools like SnowConvert. Load the extracted data into Snowflake by using a staging area in cloud storage.
6. Migrate BI tools and Data Pipeline: Snowflake supports ODBC and JDBC connections, so just change the connections from Netezza to Snowflake. The data pipeline needs to be adapted to Snowflake’s Extract Load and Transform (ELT) approach. The pipeline should run in both Netezza and Snowflake during initial migration.
7. Validate the migration: Once the data is migrated, we should thoroughly test the environment, compare and observe the results. Change BI tools, APIs, and apps to point to Snowflake.  Run parallel pipelines in both Netezza and Snowflake and verify row counts, sums of numeric fields, and string fields to ensure data consistency. Compare the functionality of applications in both Netezza and Snowflake. Check the query performance through performance testing.
8. Get Stakeholder Approval: Once the migration is completed and stable, obtain the stakeholders’ approval by showing the results obtained from both Netezza and Snowflake.

What to Do After You Migrate from Netezza to Snowflake

After migrating from Netezza to Snowflake database, some post-migration steps need to be ensured, such as:

• Pilot run: Test and run the migrated data from Netezza to Snowflake. Verify whether all the data has been migrated correctly, ensuring no data losses.
• Performance optimization: Monitor query performance and workloads optimization through available features like auto-scaling, clustering keys, and warehouse sizing.
• Security Compliance: Ensure that only authorized users have access to sensitive data through a Role-Based Access Control (RBAC) approach.
• Training and Documentation: Proper training needs to be given to the team regarding the architecture, data flows, processes, and newly added features for ongoing support and maintenance. Document the whole process, including architecture diagrams, and create usage guidelines on query writing and warehouse usage.
• Uninstall Netezza: Once all the migration is done and validation is successful, make the production environment point to Snowflake and decommission Netezza.

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