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DataStax Enterprise OpsCenter 6.8

    • About OpsCenter
      • New features
      • Key features
      • Labs features
        • Exporting and importing dashboard presets
        • Adding a Swift CLI backup location
        • Configuring named route linking
        • Viewing logs from node details
      • Architecture overview
      • OpsCenter policy for DDAC and OSS
      • Feedback about OpsCenter
    • Release notes
    • Installing OpsCenter
    • Upgrading OpsCenter
    • OpsCenter recommended settings
      • OpsCenter basic configurations
      • Cluster synchronization settings
      • Backup Service settings
      • Knowledge Base articles
    • Configuring OpsCenter
      • OpsCenter Security
        • OpsCenter SSL overview
          • Enabling/Disabling HTTPS for the OpsCenter server
          • Configuring SSL/TLS between OpsCenter and the DataStax Agents
          • Connect to DSE with client-to-node encryption in OpsCenter and the DataStax Agents
          • Editing/OpsCenter cluster connections for authentication or encryption
          • SSL configuration options for OpsCenter
        • Configuring OpsCenter role-based security
        • Encrypting sensitive configuration values
          • Activating configuration encryption
          • Creating a system key to encrypt sensitive configuration values
          • Manually encrypting a configuration value
          • Deactivating configuration encryption
        • Authenticating with LDAP
          • Configuring LDAP
          • Adding a role for an LDAP user
          • Troubleshooting OpsCenter LDAP
        • Kerberos authentication
          • Configuring OpsCenter for Kerberos authentication
          • OpsCenter Kerberos configuration options
          • Troubleshooting Kerberos in OpsCenter
        • Configuring security logging
      • Configuring alerts for events
        • SNMP alerts overview
          • Enabling SNMP alerts
        • Enabling SMTP email alerts
        • Enabling alerts posted to a URL
          • Verifying that events are posting correctly
          • Posting URL alerts to a Slack channel
      • Configuring data collection and expiration
        • Controlling data collection
        • Storing collection data on a separate cluster
      • OpsCenter DSE definitions files updates
        • Updating and configuring definitions files properties
      • Automatic failover overview
        • Enabling automatic failover
        • Failover configuration options reference
      • Backing up critical configuration data
      • Configuring named route linking
      • Configuring the OpsCenter JVM
      • Configuring the DataStax Agent JVM
        • Setting and securing the tmp directory for the DataStax Agent
        • Encrypting JMX communications
      • Changing the replication strategy for the OpsCenter keyspace
      • Configuration files for OpsCenter
        • OpsCenter configuration properties
          • Statistics reporter properties
        • Cluster configuration properties
          • Cassandra connection properties
          • Metrics Collection Properties
        • DataStax Agent configuration
        • OpsCenter logback.xml configuration
      • Customize scripts for starting and stopping DataStax Enterprise
      • Example configuration scenarios
        • Configuring for multiple regions
        • Configuring for very large clusters
    • Using OpsCenter
      • OpsCenter workspace overview
        • Ring View
        • List View
        • DataStax Agents Status View
        • Nodes Detail View
          • Node management operations
      • Configuring alerts
        • Adding an alert for agent issues
          • Troubleshooting DataStax Agent Issues
        • Adding an alert for down nodes
        • Configuring an alert for KMIP errors
        • Configuring an alert for percentage of in-memory usage
        • Configuring an alert for percentiles
      • Monitoring node operations
        • Viewing the Spark Console
        • Monitoring in-memory usage
        • Viewing logs from node details
      • Managing and maintaining nodes
        • Running cleanup
        • Performing garbage collection
        • Running compaction
        • Flushing tables
        • Decommission a node
        • Draining a node
        • Moving a node
        • Running a manual repair
        • Configure an alias for a node
      • Starting and stopping DSE
        • Starting DSE on a node
        • Stopping DSE on a node
        • Restarting DSE on a node
      • Managing keyspaces and tables
        • Keyspaces
          • Managing a keyspace
          • Managing tables
        • Browsing data deprecated
      • Cluster administration
        • Adding an existing cluster
        • Disconnecting a cluster from OpsCenter and Lifecycle Manager
        • Rebalancing a cluster overview
          • Rebalancing a cluster
          • Configuring an alert for rebalancing a cluster
        • Restarting a cluster
        • Changing the display name of a cluster
        • Downloading diagnostic data
          • Diagnostic tarball reference
          • Creating an alternate directory for diagnostic information
        • Downloading Insights diagnostic data
        • Generating a cluster report
      • OpsCenter Metrics Tooltips Reference
        • Dashboard performance metrics
        • Performance metrics overview
          • Working with metrics performance graphs
          • Organizing performance metrics presets
          • Exporting and importing dashboard presets
        • Cluster performance metrics
        • Pending task metrics
          • Pending task metrics for writes
          • Pending task metrics for reads
          • Pending task metrics for cluster operations
        • Table performance metrics
        • Tiered storage performance metrics
          • Configuring tiered storage metric graphs
          • Configuring tiered storage alerts
        • Message latency metrics
          • Adding dashboard graphs for datacenter and node messaging latency
          • Adding alerts for DC and node message latency
        • Search performance metrics
        • Graph metrics
        • NodeSync metrics
        • Thread Pool (TP) metrics
          • Viewing TP stats in Node Details
          • Enabling network backpressure
        • Dropped Messages metrics
        • Operating system performance metrics
        • Alert metrics
          • Advanced system alert metrics
    • OpsCenter 6.8 Reference
      • OpsCenter ports reference
      • Installation and configuration locations
        • Default file locations for package installations
        • Default file locations tarball installations
      • Starting, stopping, and restarting OpsCenter
        • Startup log for OpsCenter
      • Stopping, starting, and restarting DataStax Agents
    • DSE Management Services
      • Backup Service
        • Quick Video Tour: Backup Service
        • Adding a backup location
          • Adding a local file system backup location
          • Adding an Amazon S3 backup location
          • Adding an Azure backup location
        • Backing up data
          • Backing up a cluster
          • Backing up to Amazon S3
          • Backing up and restoring DataStax Graphs in OpsCenter
          • Viewing backup and restore history
          • Synchronizing backup data after an upgrade
          • Deleting backup data
        • Restoring a cluster
          • Restoring from a backup
          • Restoring a backup to a specific point-in-time
          • Monitoring sufficient disk space for restoring backups
        • Cloning cluster data
          • Cloning cluster data from a defined other location
          • Cloning cluster data from clusters managed by the same OpsCenter instance
        • Configuring the Backup Service
          • Configuring commit log backups
          • Configuring the free disk space threshold for backups
          • Configuring encryption key storage for backups
          • Configuring custom scripts to run before and after backups
          • Configuring restore to continue after a download failure
          • Backup Service configuration options
        • Troubleshooting Backup Service errors
      • NodeSync Service
        • Enabling NodeSync
        • Configuring the NodeSync refresh data interval
        • Viewing NodeSync Status
        • Configuring the NodeSync rate using LCM
        • NodeSync metrics
      • Repair Service
        • Repair Service overview
          • Subrange repairs overview
          • Distributed subrange overview
          • Incremental repairs overview
          • Repair Service behavior during environment changes
          • Estimating remaining repair time
        • Turning the Repair Service on
        • Turning the Repair Service off
        • Viewing repair status
        • Basic repair configuration
          • Configuring incremental repairs
          • Excluding keyspaces or tables from subrange repairs
          • Enabling distributed subrange repairs
          • Logging for the Repair Service
          • Basic Repair Service configuration reference
        • Advanced repair configuration
          • Adjusting or disabling the throttle for subrange repairs
          • Running validation compaction sequentially
          • Advanced Repair Service configuration reference
        • Expert repair configuration
          • Setting the maximum for parallel subrange repairs
          • Expert Repair Service configuration reference
          • Tuning Repair Service for multi-datacenter environments
        • Expedited Repair Service configuration
        • Troubleshoot Repair Service errors
        • Learn more about repairs
      • Capacity Service
        • Forecasting trends for metric graphs
        • Advanced forecast configuration
      • Best Practice Service
        • Configuring Best Practice service rules
        • Monitoring the results of Best Practice service scans
        • Best Practice Rules Reference
      • Performance Service
        • Performance Service Overview
        • Why use the OpsCenter Performance Service?
        • Enabling the OpsCenter Performance Service
        • Disabling the OpsCenter Performance Service
        • Setting permissions for the OpsCenter Performance Service
        • Tuning a database cluster with the Performance Service
          • Identifying and tuning slow queries
    • Identifying poorly performing tables
    • Monitoring node thread pool statistics
    • Troubleshooting OpsCenter
    • Lifecycle Manager
      • Overview of Lifecycle Manager
        • Supported capabilities
        • Defining the topology
        • Using configuration profiles
        • Defining repositories
        • Running jobs in LCM
          • Job types in LCM
          • Job concurrency in LCM
        • Monitoring job status
      • Installing DSE using LCM
        • Accessing OpsCenter Lifecycle Manager
        • Creating custom data directories
        • Adding SSH credentials
        • Adding a configuration profile
        • Adding a repository
        • Defining the cluster topology
          • Adding a cluster
          • Adding a datacenter
          • Adding a node
        • Running an installation job
        • Viewing job details
        • Using LCM in an offline environment
          • Required software for offline DSE installs
          • Downloading DSE in an offline environments
      • Managing SSH credentials
        • Adding SSH credentials
        • Editing SSH credentials
        • Deleting SSH credentials
        • Configuring SSH connection thresholds for LCM jobs
      • Managing configuration profiles
        • Adding a configuration profile
        • Editing a configuration profile
        • Customizing configuration profile files
        • Cloning a configuration profile
        • Deleting a configuration profile
        • Configuring an HTTP or HTTPS proxy
      • Configuring repositories
        • Adding a repository
        • Editing a repository
        • Deleting a repository
      • Defining DSE topologies
        • Managing cluster topologies
          • Adding a cluster
          • Editing a cluster
          • Deleting a cluster
          • Importing a cluster topology
        • Managing datacenter topologies
          • Adding a datacenter
          • Editing a datacenter
          • Deleting a datacenter
        • Managing node topologies
          • Adding a node
          • Editing a node
          • Deleting a node
      • Running LCM jobs
        • Running an installation job
        • Running an configure job
        • Running an upgrade job
          • Example: Upgrading DSE to a minor release using LCM
        • Aborting a job
        • Adjusting idle timeout
      • Configuring Java options
        • Choosing a Java vendor in LCM
        • Managing Java installs
        • Configuring JVM options for DSE using LCM
      • Configuring DSE security using LCM
        • Native transport authentication schemes and limitations in LCM
          • Configuring row-level access control
        • Configuring SSL/TLS for DSE
        • Configuring a JMX Connection to DSE
      • Lifecycle Manager configuration options
      • Configuration known issues and limitations
      • Using advanced configurations with LCM
        • Exporting metrics collection
        • Configuring AlwaysOn SQL
        • Configuring DSE Graph
        • Configuring the NodeSync rate
        • Configuring tiered storage
    • OpsCenter API reference for developers
      • Enable and access the Datastax Agent API
      • Authentication
      • OpsCenter configuration
      • Retrieving cluster and node information
      • Performing Cluster Operations
      • Managing Keyspaces and Tables
      • Retrieving Metric Data
      • Managing Events and Alerts
      • Schedule management
      • Backup Management and Restoring from Backups
      • Best Practice Rules
      • Hadoop
      • Spark
      • Managing Performance Service Configuration
      • User Interface
      • Agent Install and Status
      • Cluster Lifecycle Management
      • DataStax Agent API example curl commands
  • DataStax Enterprise OpsCenter 6.8
  • Using OpsCenter
  • Cluster administration
  • Rebalancing a cluster overview

Rebalancing a cluster overview

Cluster rebalancing ensures that each non-virtual node in a DataStax Enterprise cluster manages an equal amount of data. Currently, OpsCenter only supports rebalancing on clusters using the random partitioner or murmur 3 partitioner. Ordered partitioners are not supported. A rebalance is usually required only when the cluster topology has changed in some way, such as nodes were added or removed, or the replica placement strategy was changed. Configure an alert to notify you when a cluster requires rebalancing. If using role-based security, set permission to rebalance a cluster in the Cluster Topology section of the Role dialog.

A cluster is considered balanced when each node is responsible for an equal range of data. OpsCenter determines cluster balance by evaluating the partitioner tokens assigned to each node to make sure that the data ranges each node is responsible for are evenly distributed. Even though a cluster is considered balanced, it is still possible that some nodes have more data relative to others because only the number of rows (not the size of rows) managed by each node is taken into account.

The optimal path to rebalance clusters with around 100 nodes or less is determined by calculating the number of moves required and how much streaming data those moves would entail. If a cluster contains more than around 100 nodes, the optimal path is calculated based on simply the number of moves to expedite the rebalancing process.

When rebalancing a cluster, OpsCenter performs the following actions:

  • Calculates appropriate token ranges for each node and identifies nodes that need to move.

  • Makes sure that there is appropriate free space to perform the rebalancing.

  • Moves nodes one node at a time so as to lessen the impact on the cluster workloads. A move operation involves changing the partitioner token assignment for the node, thus changing the range of data that the node is responsible for. A move streams data from other nodes.

  • Runs cleanup after a move is complete on a node. A cleanup operation removes rows that a node is no longer responsible for.

Disconnecting a cluster from OpsCenter and Lifecycle Manager Rebalancing a cluster

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