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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
  • DSE Management Services
  • Repair Service
  • Repair Service overview
  • Subrange repairs overview

Subrange repairs overview

Subrange repairs

Subrange repairs repair a portion of the data that a node is responsible for. After an entire cluster has been repaired, including any independently running incremental repairs, the Repair Service recalculates the list of subranges to repair and starts over. Repairing an entire cluster one time is referred to as a repair cycle.

Excluding keyspaces and tables

Specify entire keyspaces or certain tables for subrange repairs to ignore, in addition to the default system keyspaces, certain rollup tables, and so forth. See Excluding keyspaces or tables from subrange repairs.

Prioritizing tasks

When running subrange repairs, the Repair Service determines which nodes have the least traffic in terms of compactions or streaming between nodes. Both streaming and compaction activities are represented in the Repair Service Status. The prioritization_page_size option limits the number of possible repair tasks for the Repair Service to review when selecting a low impact repair. Increasing the page size is more CPU-intensive for the Repair Service but could result in more optimal dispatching of repairs to the cluster.

The prioritization_page_size is an expert option that should not be changed without guidance from DataStax Support.

Offline splits

Offline splits refers to offline task generation (determining splits for subrange repairs) by the Repair Service when a node is down or unavailable.

Ideally, during planning of a subrange repair, the Repair Service in the OpsCenter daemon retrieves the token subrange splits from each OpsCenter agent in the cluster, since each agent is able to retrieve the necessary data from its node to determine the optimal set of subrange splits for each keyspace to repair. However, if either the agent or node is offline or unavailable, the Repair Service falls back to splitting the token range for that node. This is less than optimal because the OpsCenter daemon cannot access the information about counts and sizes of partitions that belong to a token range for an unavailable node.

The offline_splits option controls the number of subranges per keyspace to split the primary range into for a node. The goal for each subrange is to have no more than approximately 32,000 partitions per keyspace. It is most optimal to repair a subrange that contains 32,000 partitions because that is the largest number of partitions in a range that can be repaired in a single attempt without streaming more data than necessary between nodes.

The default for the offline_splits option is 256. For sparsely populated clusters, the default might suffice. For clusters having much more densely populated nodes, it could make sense to increase the default value. The system.size_estimates table is regenerated every five minutes, and gives some indication of how many partitions are contained within each node’s primary range for each keyspace and table.

Configuration options for offline splits and its related options are considered expert-level options that should not be adjusted without guidance from DataStax Support.

The Repair Service log indicates if offline splits had to be used for any node.

Throttling subrange repair time

The Repair Service automatically throttles subrange repairs when the current repair cycle is estimated to finish significantly before the deadline specified by the time to completion.

The time_to_completion_target_percentage configuration option controls the frequency and pace of the subrange repair process. The throttle slows repairs or reduces parallel repair processes as necessary to prevent overloading the cluster while still completing a repair cycle within the specified time window designated by the Time to completion value. The default value for the target percentage to complete a repair is 65%.

Because certain repair config options are tempered by the percentage option, a judicious approach to configuring advanced repair options can optimize repair performance for various production environments and avoid issues due to misconfiguration. The majority of default settings typically do not require adjustment unless advised by a DataStax Support professional.

If there are any issues with the Repair Service configuration, the Repair service not configured correctly rule in the Best Practice Service fails and provides guidance as to incorrectly configured options, unless the rule has been turned off.

DataStax recommends only manually adjusting the max_parallel_repairs, changing min_repair_time and other advanced or expert options only if the time_to_completion_percentage throttle is not is use. See Adjusting or disabling the throttle for subrange repairs.

Incremental repairs are exempt from this throttle.

See Adjusting or disabling the throttle for subrange repairs for more information.

Calculating parallel repairs

The Repair Service uses an average of the throughput of recent repairs to calculate the average throughput. The average throughput is used to dynamically determine the number of parallel repairs required to complete a repair during a current cycle. The num_recent_throughputs option determines the maximum number of recent throughputs used to calculate average throughput. The default value is 500. Calculating parallel repairs also depends on a corresponding minimum throughput value before commencing its calculation. The min_throughput option represents the throughput required for any given repair task to be considered when determining the number of parallel repairs. The default value is 512 bytes/sec. See Setting the maximum for parallel subrange repairs for more information.

Maximum pending repairs

Before issuing a new subrange repair, the Repair Service checks for the number of repairs both running or waiting to run. If the configured maximum pending repairs threshold would be exceeded, the repair skips that node for the time being to avoid overwhelming an already swamped node. The repair task is moved to the back of the pending repair tasks queue to retry later and an alert is fired.

Subrange repair status

View progress, statistics, and details for subrange repairs in the Repair Status tab.

Repair Service overview Distributed subrange overview

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