Package org.apache.geode.cache.util

Class AutoBalancer

java.lang.Object
org.apache.geode.cache.util.AutoBalancer
All Implemented Interfaces:
Declarable
@Experimental("The autobalancer may be removed or the API may change in future releases") public class AutoBalancer extends Object implements Declarable
Re-balancing operation relocates data from heavily loaded members to lightly loaded members. In most cases, the decision to re-balance is based on the size of the member and a few other statistics. AutoBalancer monitors these statistics and if necessary, triggers a re-balancing request. Auto-Balancing is expected to prevent failures and data loss.

This implementation is based on ConfigInitialization implementation. By default auto-balancing is disabled. A user needs to configure AutoBalancer during cache initialization GemFireCache.getInitializer()

In a cluster only one member owns auto-balancing responsibility. This is achieved by grabbing a distributed lock. In case of a failure a new member will grab the lock and manage auto balancing.

AutoBalancer can be controlled using the following configurations

  1. SCHEDULE
  2. TBD THRESHOLDS

  • Field Details

    • SCHEDULE

      public static final String SCHEDULE
      Use this configuration to manage out-of-balance audit frequency. If the auditor finds the system to be out-of-balance, it will trigger re-balancing. Any valid cron string is accepted. The sub-expressions represent the following:
      1. Seconds
      2. Minutes
      3. Hours
      4. Day-of-Month
      5. Month
      6. Day-of-Week
      7. Year (optional field)

      For. e.g. 0 0 * * * ? for auditing the system every hour

      See Also:

    • SIZE_THRESHOLD_PERCENT

      public static final String SIZE_THRESHOLD_PERCENT
      Use this configuration to manage re-balance invocation. Rebalance operation will be triggered if the total number of bytes rebalance operation may move is more than this threshold, in percentage of the total data size.

      Default value DEFAULT_SIZE_THRESHOLD_PERCENT

      See Also:

    • DEFAULT_SIZE_THRESHOLD_PERCENT

      public static final int DEFAULT_SIZE_THRESHOLD_PERCENT
      Default value of SIZE_THRESHOLD_PERCENT. If 10% of data is misplaced, its a good time to redistribute buckets
      See Also:

    • MINIMUM_SIZE

      public static final String MINIMUM_SIZE
      In the initial data load phases, SIZE_THRESHOLD_PERCENT based rebalance invocation may be unnecessary. Rebalance should not be triggered if the total data size managed by cluster is too small. Rebalance operation will be triggered if the total number of bytes rebalance operation may move is more than this number of bytes.

      Default value DEFAULT_MINIMUM_SIZE

      See Also:

    • DEFAULT_MINIMUM_SIZE

      public static final int DEFAULT_MINIMUM_SIZE
      Default value of MINIMUM_SIZE. In the initial data load phases, SIZE_THRESHOLD_PERCENT based rebalance invocation may be unnecessary. Do not rebalance if the data to be moved is less than 100MB
      See Also:

    • AUTO_BALANCER_LOCK_SERVICE_NAME

      public static final String AUTO_BALANCER_LOCK_SERVICE_NAME
      Name of the DistributedLockService that AutoBalancer will use to guard against concurrent maintenance activity
      See Also:

    • AUTO_BALANCER_LOCK

      public static final Object AUTO_BALANCER_LOCK

  • Constructor Details

    • AutoBalancer

      public AutoBalancer()

    • AutoBalancer

      public AutoBalancer(org.apache.geode.cache.util.AutoBalancer.AuditScheduler scheduler, org.apache.geode.cache.util.AutoBalancer.OOBAuditor auditor, org.apache.geode.cache.util.AutoBalancer.TimeProvider clock, org.apache.geode.cache.util.AutoBalancer.CacheOperationFacade cacheFacade)

  • Method Details

    • initialize

      public void initialize(Cache cache, Properties props)
      Description copied from interface: Declarable
      Initializes a user-defined object, owned by the given cache, using the given properties. Note that any uncaught exception thrown by this method will cause the Cache initialization to fail. Note that if this method is implemented then the deprecated init method should not be implemented. The product will call both methods assuming that only one will have a non-default implementation.
      Specified by:
      initialize in interface Declarable
      Parameters:
      cache - the cache that owns this declarable
      props - Contains the parameters declared in the declarative xml file.

    • init

      @Deprecated public void init(Properties props)
      Deprecated.
      as of Geode 1.5 use initialize instead.
      Description copied from interface: Declarable
      Initializes a user-defined object using the given properties. Note that any uncaught exception thrown by this method will cause the Cache initialization to fail.
      Specified by:
      init in interface Declarable
      Parameters:
      props - Contains the parameters declared in the declarative xml file.

    • getCacheOperationFacade

      public org.apache.geode.cache.util.AutoBalancer.CacheOperationFacade getCacheOperationFacade()

    • destroy

      public void destroy()