Package org.apache.accumulo.core.spi.fs

Interface VolumeChooser

All Known Implementing Classes:
DelegatingChooser, PreferredVolumeChooser, RandomVolumeChooser, SpaceAwareVolumeChooser
public interface VolumeChooser
Helper used to select a volume from a set of Volume URIs.

Volumes will be selected based on defined option criteria. Note: Implementations must be threadsafe.
VolumeChooser.equals will be used for internal caching.

Property Details:
Property.GENERAL_ARBITRARY_PROP_PREFIX and Property.TABLE_ARBITRARY_PROP_PREFIX can be used to define user-specific properties to ensure separation from Accumulo System defaults.
Note: The default VolumeChooser implementation is set by Property.GENERAL_VOLUME_CHOOSER.

Since:
2.1.0

  • Method Details

    • choose

      String choose(VolumeChooserEnvironment env, Set<String> options)
      Choose a volume from the provided options.
      Parameters:
      env - the server environment provided by the calling framework
      options - the list of volumes to choose from
      Returns:
      a volume from the list of volume options

    • choosable

      Set<String> choosable(VolumeChooserEnvironment env, Set<String> options)
      Return the subset of all possible volumes that could be chosen across all invocations of choose(VolumeChooserEnvironment, Set).
      This is currently used to determine if the chosen volumes can support the required filesystem operations for write ahead logs.
      There may be other use cases in the future.