Keyspace replication strategy cassandra Alternatively, in a cluster in a single data center, use the default data center name, for example, datacenter1, and skip registering the name in the properties file. Default Value: KEYSPACE ALTER KEYSPACE Changes keyspace replication strategy and enables or disables commit log. By understanding the different replication strategies and how to configure them, you can optimize your Cassandra deployment for your specific use case. Aug 21, 2025 · To ensure replication between datacenters, connect to Cassandra Query Language Shell (CQLSH) and use the following CQL query to update the replication strategy in each keyspace to include all the datacenters across the cluster. SimpleStrategy: SimpleStrategy defines a replication factor for whole cluster. 在本教程中，您将学习如何使用Cassandra-修改KeyspaceAlterKeyspaceALTERKEYSPACE可用于AlterKeyspace的副本数和durable_writes等属性。下面给 2 days ago · A. Below is the syntax to create a keyspace: Replication strategy Cassandra stores replicas on multiple nodes to ensure reliability and fault tolerance. NetworkTopologyStrategy: Highly recommended for most deployments. Modify the replication strategy or replication factor of a keyspace. 1. When you create a keyspace, specify a Replication strategy class and factor settings for replicating keyspaces. The replication strategy is a required attribute of a keyspace. A keyspace contains one or more tables and defines the replication strategy for all the tables it contains. A keyspace is the outermost container of data. The discrepancy between schemas are detected via gossip, and triggering the process of data update. It is common for a cluster to define only one keyspace for an active application. Default Value: KEYSPACE The load assigned to each node will be close to proportional to its number of vnodes. SimpleStrategy from replication_strategy_warn_list configuration option, or make it into an error by listing this replication strategy on replication_strategy_fail_list. We can simply define replication strategy and RF (Replication Factor) to create multiple copies of data. locator. Understanding these strategies is crucial for designing a reliable and scalable Cassandra architecture. The sub-options depends which replication strategy we choose. They determine how data is distributed and replicated across nodes. Jan 24, 2022 · Ex: CREATE KEYSPACE pythian WITH replication = {‘class’: ‘SimpleStrategy’, ‘replication_factor’: 3}; In the above example, we created a keyspace called Pythian using SimpleStrategy with replication factor 3. A keyspace defines options that apply to all the keyspace’s tables. Feb 18, 2022 · To change the strategy, two steps are required. This blog shows you how to backup Apache© Cassandra© databases and restore them after a failure. When you change the replication factor of a keyspace, you affect each node that the keyspaces replicates to (or no longer replicates to). 1 replica placement strategy. It defines important properties including replication strategy and replication factor that determine how data is distributed and replicated across the cluster. To create a keyspace, Cassandra Query Language has the CREATE KEYSPACE statement with the following simplified Apr 18, 2001 · About the Cassandra replication factor Cassandra stores data replicas on multiple nodes to ensure reliability and fault tolerance. Once you have finished evaluating and refining the physical model, you’re ready to implement the schema in CQL. A keyspace is like RDBMS database which contains column families, indexes, user defined types, data center awareness, strategy used in keyspace, replication factor, etc. After opening cassandra CQL shell i ran the below command Create keyspace KeyspaceName with replicaton{'class':'simplestrategy',' The Cassandra Replication Strategy is used to provide the high availability, fault tolerance, and reliability of data by replicating it on multiple nodes. A keyspace acts as a container that holds tables and defines the replication strategy for data distribution. That‘s why Cassandra gives you ALTER KEYSPACE – the ability to modify keyspaces on the fly once they‘re in production. 2 days ago · A. Creates a top-level keyspace. Replica placement strategy Mar 6, 2024 · I am trying to do the 101 course but when I tried this *CREATE KEYSPACE scyllaU WITH REPLICATION = {'class' : 'NetworkTopologyStrategy', 'DC1' : 3, 'DC2' : 2};* I got this ConfigurationException: Unrecognized strategy option {DC2} passed to org. Aug 27, 2018 · I have installed "DataStax Distribution of Apache Cassandra 3. ALTER KEYSPACE KeySpace Name WITH replication = {'class': Strategy name, 'replication_factor' : No. Given below is the syntax for creating a keyspace using the statement CREATE KEYSPACE. cassandra. Sep 27, 2022 · In this article, we will learn about what a keyspace is in Cassandra and its various operations. Cassandra uses a configurable replication strategy to determine how data is replicated across the cluster. To change the strategy, alter the distribution of nodes within multiple datacenters by adding a datacenter, and then add data to the new nodes in the new datacenter and remove nodes from the old datacenter. options are one or more of the following: REPLICATION – A map that indicates the replication strategy for the keyspace: SingleRegionStrategy – For a single-Region keyspace. In of the document you linked (), you needed to specify just the existing DCs when changing the replication settings in preparation for setting up the new DCs. For more information about replication, see Data replication. For more about replication strategy options, see Changing keyspace replication strategy. Altering the distribution of nodes within multiple datacenters when data is present should be Jan 26, 2022 · Learn why and how you should change the default replication for the system_auth keyspace in Cassandra with Mario Tavares Jan 15, 2023 · Replication Strategy defines how data is replicated across all the nodes in the cluster. Jun 19, 2024 · Create keyspace University with replication={'class':SimpleStrategy,'replication_factor': 3}; After successful execution of command “Create Keyspace”, Keyspace University will be created in Cassandra with strategy “SimpleStrategy” and replication factor 3. Tables are located in keyspaces. May 18, 2023 · In Cassandra, a keyspace is a top-level namespace that groups related tables together. The replication factor determines the number of copies of data that are stored in the cluster. Altering a KeySpace ALTER KEYSPACE can be used to alter properties such as the number of replicas and the durable_writes of a KeySpace. Mar 10, 2025 · Introduction to Keyspaces and Tables in CQL Programming Language In CQL (Cassandra Query Language), keyspaces are like databases – they define the outermost container for data and store tables, user-defined types, and other database objects. ALTER TABLE Modifies the columns and properties of a table, or modify ALTER TYPE Modifies an existing user-defined Feb 18, 2022 · You define the replication factor for each datacenter. This is different from the consistency level requested by each write which may be lower in order to facilitate availability. Only supported with the Murmur3Partitioner. If you want to look at the replication factor of a given keyspace, simply execute SELECT * FROM system_schema. Each keyspace manages replication strategies, deciding how data is copied across nodes. 0, it is no longer possible to specify invalid DCs with the or commands (). Reasons you may want Transient Replication (CASSANDRA-14404) is an experimental feature designed for expert Apache Cassandra users who are able to validate every aspect of the database for their application and deployment. Jul 12, 2025 · Changing the Replication Strategy: In case of modifying we can set the RF (replication factor) and replication strategy at keyspace level. For more information about keyspaces, see the following topics: Jul 17, 2019 · Database backup and recovery is one of the crucial day-to-day activities that a database administrator (DBA) performs. let's understand this with an example. A keyspace is a logical grouping of tables that share the same replication factor and replication strategy. Data replication is configured per keyspace in terms of replication factor per data center and the replication strategy. Replication Strategy : NetworkTopologyStrategy Syntax ALTER KEYSPACE <identifier> WITH <properties> i. . It’s where you define how your data gets replicated across the cluster. Dec 27, 2023 · Replication factor Replication strategy Durable writes setting The optimal configuration values depend heavily on your data volumes, query patterns, and infrastructure size. Feb 18, 2022 · Changing the strategy of a keyspace from SimpleStrategy to NetworkTopologyStrategy. Here is the schema for the hotel keyspace, using CQL’s comment feature to document the query pattern supported by each table: Feb 18, 2022 · Cassandra stores replicas on multiple nodes to ensure reliability and fault tolerance. Updating the replication factor Increasing the replication factor increases the total number of copies of keyspace data stored in a Cassandra cluster. Defining those upfront when you‘re first building a system is challenging. To have cassandra-stress create a keyspace with this strategy you would need to drop any Options to set replication strategy. It has two properties: replication and durable_writes. Set this too low, and a single failure can wipe out data. Data Model Basics: The Blueprint of Your Data Cassandra's data model is schematized, though flexible, and centers around a few key constructs: Keyspaces: Analogous to a schema or database in relational systems, a keyspace defines the replication strategy and replication factor for its tables. Jul 8, 2025 · Learn About What Is A Cassandra Keyspaces,⭐Replication Strategies, Syntax, Best Practices, And Common Pitfalls To Avoid When Managing Distributed Database Structures. Apr 3, 2015 · What i am looking for is examples how i would tell cassandra to use a certain keyspace strategy (consistently and/or application dependent). Oct 12, 2025 · Replication strategies define how and where copies of data (replicas) are stored. apache. Cassandra supports pluggable replication strategies, which determine which physical nodes act as replicas for a given token range. May 19, 2016 · Replication is completely dependent on the replication strategy of your keyspace and the layout of your cluster. When data is written to Cassandra every DC will fulfill the replication factor as defined in Jul 30, 2024 · Here are some best practices to keep in mind: 1. A replication strategy determines the nodes where replicas are placed. Contents Simple read and write examples View schema help Populate the database Change the replication strategy Run a mixed workload Standard mixed read/write workload keyspace for a single node Split up a load over multiple cassandra-stress instances on different nodes Run cassandra-stress with authentication Run cassandra-stress with authentication and SSL encryption Run cassandra-stress Jul 6, 2023 · What is Keyspace in Cassandra? Keyspace in Cassandra is an object which is a collection of one or more column families (tables) schema. Generally you should set the replication strategy greater than one, but no more than the number of nodes in the cluster. Learn how Cassandra replication and partitioning works with this detailed guide including examples, best practices, and troubleshooting tips. In Cassandra 4. ALTER KEYSPACE Changes keyspace replication strategy and enables or disables commit log. CREATE KEYSPACE [IF NOT EXISTS] keyspace_name Keyspace names can have up to 48 alpha-numeric characters and contain underscores; only letters and numbers are supported as the first character. It is conceptually similar to a "database" in a relational database management system. This article explains SimpleStrategy and NetworkTopologyStrategy, how they work, and when to use each. Choosing the right replication settings can impact data availability, fault tolerance, and performance. 9 and I did the same way how 'help create keyspace' tell me. For better understanding please refer Replication Strategy in Cassandra article. ALTER ROLE Changes password and sets superuser or login options. Keyspace management is located in the CqlSession configuration, which has the KeyspaceSpecification and startup and shutdown CQL script execution. keyspaces; and it will print all replication information you need. For information about the replica placement strategy, see Apache Cassandra ™ 2. Mar 7, 2025 · Replication Strategy: There are different replication strategies available in Cassandra, such as SimpleStrategy and NetworkTopologyStrategy. When you add keyspaces that have the Simple Strategy replication factor to an existing Cassandra cluster, then the following rules apply to backups: If you have a user-defined subclient that contains Simple Strategy keyspaces, then the you need to add the keyspace to the subclient (Subclient Properties dialog box, Cassandra Contents tab). May 26, 2020 · If it doesn't work, you may need to add 6 new nodes (instead of 4) and decommission the existing 2 nodes. For production work, the NetworkTopologyStrategy class must be set. There are two main strategies: SimpleStrategy: Use only for a single datacenter and one rack. My Cassandra cluster is on AWS, Cassandra 2. Cassandra stores replicas on multiple nodes to ensure reliability and fault tolerance. Dec 26, 2024 · Understanding Cassandra’s Data Model Cassandra is a wide-column store, and its data model is designed to scale horizontally and handle massive amounts of data across distributed nodes. Learn about consistency levels, network topology strategy, rack awareness configurations, hinted handoff handling, read/write path optimizations, and monitoring essentials. Cassandra Create Keyspace To communicate with Cassandra the Cassandra Query Language (CQL) is used. (Required) NetworkTopologyStrategy – Specify at least two AWS Regions. Sep 8, 2025 · What is Apache Cassandra? Cassandra is a distributed database management system designed for handling a high volume of structured data across commodity servers. Aug 28, 2024 · The DCSimpleStrategy is a replication strategy that divides the nodes into a single data center and replicates data across all nodes in the data center. This layout is defined by two things, Datacenters and Racks. Cassandra arranges the nodes in a cluster, in a ring format, and assigns data to them. The data inserted in this keyspace will be replicated to the three nodes, in one datacenter and across different racks. Sep 26, 2025 · When you add keyspaces that have the Simple Strategy replication factor to an existing Cassandra cluster, then the following rules apply to backups: If you have a user-defined subclient that contains Simple Strategy keyspaces, then the you need to add the keyspace to the subclient (Subclient Properties dialog box, Cassandra Contents tab). It seems like because of replication strategy that is used for system_auth, it can't replicate user credentials to all the nodes in cluster, so Jan 22, 2024 · You may suppress this warning by delisting org. Aug 28, 2024 · // Create a Keyspace with SimpleStrategy replication String CREATE_KEYSPACE = "CREATE KEYSPACE mykeyspace WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3}"; NetworkTopologyStrategy # The NetworkTopologyStrategy is a more advanced replication strategy that takes into account the physical topology of the data center. It is defined per keyspace and is set during keyspace creation. # allocate_tokens_for_keyspace: KEYSPACE # Replica factor is explicitly set, regardless of keyspace or datacenter. Track a metric per keyspace indicating whether replication achieved the ideal consistency level for writes without timing out. A keyspace groups related tables that are relevant for one or more applications. A keyspace is like a database in traditional relational systems. Replication refers to the number of copies stored within a cluster. ALTER KEYSPACE “KeySpace Name” WITH replication = {'class': ‘Strategy name’, 'replication_factor' : ‘No. CREATE KEYSPACE testkeyspace with placement_strategy = 'org. It is common for a cluster to define only one keyspace for an actie application. To set up a keyspace, see creating a keyspace. The following table lists all the replica placement strategies. If deploying an entirely new database, the “twc” keyspace will be created with the replication strategy and factors specified here. # Replica factor is determined via the replication strategy used by the specified # keyspace. A keyspace is an object working similar to an RDBMS database. After modifying the keyspace replication, execute nodetool repair -full on each node in your Cassandra cluster to ensure data is fully replicated and consistent across the cluster. 0". Durable Writes: It is recommended to set durable_writes to true when creating a keyspace. For production, you must use NetworkTopologyStrategy. Cassandra forces keyspace names to lowercase when entered without quotes. About the Cassandra replication factor Cassandra stores data replicas on multiple nodes to ensure reliability and fault tolerance. Feb 10, 2024 · A keyspace could be used to group tables serving a similar purpose from a business perspective like all transactional tables, metadata tables, use information tables etc. Jul 12, 2025 · Here’s an example that shows how to create a keyspace named App_data: you must read replication strategy in Cassandra for better understanding. It provides logical separation and isolation of data within a Cassandra cluster. In Cassandra, "Create Keyspace" command is used to create keyspace. By far the most common production scenario would be to use NetworkTopologyStrategy and a replication factor of 3. Tables, materialized views, indexes and other schema objects are always defined within a keyspace. It defines the replication strategy About the Cassandra replication factor Cassandra stores data replicas on multiple nodes to ensure reliability and fault tolerance. Using the SimpleStrategy class is fine for evaluating Cassandra. A replication factor of one means that there Description ALTER KEYSPACE changes the map that defines the replica placement strategy and/or the DURABLE_WRITES value. Watch for issues like unavailable exceptions and overloaded nodes when managing keyspaces. Jul 12, 2025 · It is not permissible to creating keyspace with LocalStrategy class if we will try to create such keyspace then it would give an error like "LocalStrategy is for Cassandra's internal purpose only". Replica factor is determined via the replication strategy used by the specified keyspace. The choice of strategy depends on the deployment architecture. 9. The load assigned to each node will be close to proportional to its number of vnodes. Cassandra handles the huge amount of data with its distributed architecture. In syntax we have to use 'class' sub-option which defines replication strategy. Easily expandable to multiple Dec 27, 2023 · Now a core component of any replication strategy… Carefully Considering Replication Factor A key setting for replication in Cassandra is the replication factor which controls how many redundant copies to keep for high availability. The replication strategy controls how the data is distributed across the cluster. To query Cassandra, create and use a keyspace. The total number of replicas for a keyspace across a Cassandra cluster is referred to as the keyspace's replication factor. Mar 7, 2024 · Explore advanced replication strategies for Apache Cassandra in multi-datacenter deployments. A keyspace is created with a strategy. This ensures data durability and availability. Data is placed on different machines with more than one replication factor that provides high availability and no single point of failure. Columns define the typed schema for a single datum in a table. 15 using vnodes, the cluster's snitch is configured to Ec2Snitch, but the keyspace the developers created has replication class SimpleStrategy = 3. The replication strategy is an important keyspace option, as is the replication factor. The replication strategy for each Edge keyspace determines the nodes where replicas are placed. In Cassandra, a namespace that specifies data replication on nodes is known as a Keyspace. ALTER MATERIALIZED VIEW Changes the table properties of a materialized view. Feb 18, 2022 · The cassandra-stress tool creates a keyspace called keyspace1 and within that, tables named standard1 or counter1, depending on what type of table is being tested. To set the replica placement strategy, construct a map of properties and values, as shown in the table of map properties on the CREATE KEYSPACE reference page. Jul 12, 2025 · In this article, we are going to discuss how we can change the replication factor in both simple and network topology replication strategy. It is an outermost container of data that defines the replication strategy and other options, particularly for all the keyspace tables. To set the replication strategy for a keyspace, see CREATE KEYSPACE. For production use or for use with mixed workloads, use the NetworkTopologyStrategy class. Feb 18, 2022 · Increasing the replication factor increases the total number of copies of keyspace data stored in a Cassandra cluster. A replication factor of one means that there May 4, 2018 · The system_schema keyspace (and system as well) has LocalStrategy as replication strategy - in this case, all changes applied only on current node. The replication factor determines how many copies of the data are made. For an existing database, you will have to manually edit the keyspace replication parameters (see Cassandra Keyspace Configuration below). You can have multiple keyspaces with different DCs and replication factors depending on how many copies and where you want your data replicated to. Of replicas’}; The properties of ALTER KEYSPACE are same as CREATE KEYSPACE. Feb 18, 2022 · CREATE KEYSPACE [IF NOT EXISTS] keyspace_name Keyspace names can have up to 48 alpha-numeric characters and contain underscores; only letters and numbers are supported as the first character. Once you've managed to re-provisioned the nodes and Changing the strategy of a keyspace from SimpleStrategy to NetworkTopologyStrategy. What is Keyspace? A keyspace is an object that is used to hold column families, user defined types. Syntax: The replication option is to specify the Replica Placement strategy and the number of replicas wanted. Contribute to apache/cassandra development by creating an account on GitHub. (Optional) Nov 12, 2023 · Adjust replication strategies and configurations per keyspace based on usage profiles and patterns. Jan 8, 2024 · The first thing to remember is that a keyspace in Cassandra is much like a database in RDBMS. Feb 18, 2022 · Keyspaces are designed to control data replication for a set of tables. Feb 24, 2017 · I'm trying to configure authentication on Cassandra. Technologies: Cassandra (Data Replication shown via keyspace settings), Python cassandra-driver Aug 19, 2016 · While this definition is a reasonable choice for a simple default, it’s important to note that this is unlikely to be representative of a keyspace you would want to run in production. Keyspace: Specifies the replication strategy for a dataset across different datacenters. ALTER TABLE Modifies the columns and properties of a table, or modify ALTER TYPE Modifies an existing user-defined Feb 11, 2025 · Cassandra Data Model Overview Keyspace: The Big Container The keyspace is the top-level structure in Cassandra, kind of like a database in relational systems. It holds column families, the strategy used in the keyspace, indexes, user-defined types, replication factor, data centre awareness, etc. It is similar to a database in the SQL world, but with some differences. Choose an arbitrary data center name and register the name in the properties file of the snitch. In a created keyspace, we can alter the replication factor, strategy name and the durable_writes properties using the “ALTER keyspace” command in Cassandra. A keyspace has a set of attributes that define the wide behavior like replication factor, datacenter awareness, the strategy used to hold the Feb 16, 2023 · You cannot specify a non-existent DC when changing the replication settings of a keyspace. com Configuring replication in Cassandra is crucial for ensuring data availability and durability. Apr 18, 2005 · About the Cassandra replication factor Cassandra stores data replicas on multiple nodes to ensure reliability and fault tolerance. e. Once enabled, Cassandra creates a hard link to each SSTable flushed or streamed locally in a backups/ subdirectory of the keyspace data. Of replicas}; The properties of ALTER KEYSPACE are same as Dec 24, 2014 · The replication factor On the surface, setting the replication factor seems to be a fundamentally straightforward idea. When you use NetworkToplogyStrategy, during creation of the keyspace, you use the datacenter names defined for the snitch used by the cluster. To place replicas in the correct location, Cassandra requires a keyspace definition that uses the snitch A keyspace is created with a replication strategy. Feb 18, 2022 · Replication strategy is defined per keyspace, and is set during keyspace creation. To change the strategy, two steps are required. A database backup is a copy of your data that can be used to recover the data in the event of data loss. Mar 20, 2019 · A similar keyspace structure looks like this: Creating a keyspace: In order to create a keyspace in Cassandra, we have to specify the replication strategy, replication factor, datacenter name, and the durable writes. This example uses the default data center name in Cassandra with a replication factor of 3. CREATE KEYSPACE mykeyspace WITH REPLICATION = { 'class' : 'DCSimpleStrategy', 'replication_factor' : 3 A keyspace in Cassandra is the top-level container for tables, similar to a database in relational database systems. When data is written to Cassandra every DC will fulfill the replication factor as defined in Transient Replication (CASSANDRA-14404) is an experimental feature designed for expert Apache Cassandra users who are able to validate every aspect of the database for their application and deployment. Follow step-by-step instructions and examples to set up a keyspace for data organization and replication. See full list on baeldung. In Cassandra, the keyspace is somewhat analogous to a database in RDBS. You configure Cassandra with the number of replicas you want to maintain (during keyspace creation), and the system dutifully performs the replication for you, thus protecting you when something goes wrong. Every keyspace of data has its own replication strategy. Jan 18, 2016 · A cluster doesn't have a replication factor, however your keyspaces does. A good general rule is one keyspace per application. Table: Tables are composed of rows and columns. Introduction to Replication Replication in Cassandra is the process of storing copies of data across multiple nodes. NetworkTopologyStrategy for keyspace scyllau I am on mac with docker Jan 15, 2018 · CREATE KEYSPACE cycling WITH REPLICATION = {'class':'SimpleStrategy', 'replication_factor':1}; If you want to specify replication by datacenter then you need to use the NetworkTopologyStrategy, in which case the create statement would be: Feb 18, 2022 · A simple example of querying Cassandra by creating a keyspace and then using it. I digged some more in the cassandra docs and think i got a better aubderstanding about the use of keyspace. Design Keyspaces with Replication in Mind The replication strategy and factor are critical components of a keyspace. In the image below To configure data replication in Cassandra-based databases, you need to define a keyspace and specify the replication strategy and replication factor. Meenakshi Syamkumar walk a token ring (in Cassandra, or other consistent hashing implementation) to identify multiple nodes responsible for a given row (while potentially skipping duplicate nodes in the same "failure domain") Apr 3, 2020 · Essentially you can easily create a globally distributed Cassandra cluster where data written to the local DC is asynchronously replicated to all the other DCs in the keyspace. A cluster contains one keyspace per node. Keyspaces serve as containers for tables. Learn how to create a keyspace in Apache Cassandra, a distributed NoSQL database. Options to set replication strategy. Given below is the syntax of this command. Default Value: KEYSPACE Apr 25, 2020 · ALTER KEYSPACE keyspace_name WITH REPLICATION = { ‘class' : replication_strategy_class, ‘replication_factor' : n } AND DURABLE_WRITES = boolean_value; Example ALTER KEYSPACE demo_keyspace Replication property is mandatory when we create Keyspace. Configure the replica placement strategy, replication factor, and durable writes setting. Use these properties and values to construct the map. Or should I change the system keyspaces strategy and replication factor too? Yes, you should set the same keyspace replication definition on the following keyspaces: system_auth, system_traces, and system_distributed. Replica placement strategy Cassandra stores copies (replicas) of data on multiple nodes to ensure reliability and fault tolerance. Here’s what you’ll configure in a keyspace: Replication factor: This decides how many copies of your data exist across the cluster. The replication factor for each Region is three. The primary components of the Cassandra data model include: Keyspaces: The top-level container in Cassandra. That means being able to check that operations like reads, writes, decommission, remove, rebuild, repair, and replace all work with your queries, data, configuration, operational practices, and Feb 29, 2020 · The keyspace created with multiple DC's generally has the following structure: CREATE KEYSPACE cycling WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'datacenter1' : 3, 'datacenter2' : 2 } AND DURABLE_WRITES = true ; Note that the datacenter1 will have 3 replicas of row and 2 in datacenter2. Apache Cassandra®. A keyspace is a namespace for a set of tables sharing a data replication strategy and some options. Using Replication we can define the number of nodes where replica will be placed. CQL property map keys Jul 12, 2025 · In Apache Cassandra, we can create multiple copies of data at the time of keyspace creation. Syntax ALTER KEYSPACE <identifier> WITH <properties> i. Feb 1, 2013 · I am trying to create keyspace in cassandra1. Altering the distribution of nodes within multiple datacenters when data is present should be accomplished by adding a datacenter, and then adding data to the new nodes in the new datacenter and removing nodes from the old datacenter. A keyspace in Cassandra is a namespace that defines data replication on nodes. Feb 18, 2022 · Change the cycling keyspace to NetworkTopologyStrategy in a single data center and turn off durable writes (not recommended). Incremental backups of system tables are also created. Description CREATE KEYSPACE creates a top-level namespace and sets the keyspace name, replica placement strategy class, replication factor, and DURABLE_WRITES options for the keyspace. The basic attributes of a Keyspace in Cassandra are − Replication factor − It is the number of machines in the cluster that will receive copies of the same data. Keyspace Keyspace is the outermost container for data in Cassandra. You can also use the alias ALTER SCHEMA. For development, the SimpleStrategy class is acceptable. Keyspaces and Lifecycle Scripts The first thing to start with is a Cassandra keyspace. For development work, the SimpleStrategy class is acceptable.