6.1. Cache Pool Commands

  • addPool

    Adds a new Cache Pool.

    Usage:

    hdfs cacheadmin -addPool <name> [-owner <owner>] [-group <group>] 
    [-mode <mode>] [-limit <limit>] [-maxTtl <maxTtl>]

    Options:

    Option Description
    <name> The name of the new pool.
    <owner> The user name of the owner of the pool. Defaults to the current user.
    <group> The group that the pool is assigned to. Defaults to the primary group name of the current user.
    <mode> The UNIX-style permissions assigned to the pool. Permissions are specified in octal, e.g., 0755. Pool permissions are set to 0755 by default.  
    <limit> The maximum number of bytes that can be cached by directives in the pool, in aggregate. By default, no limit is set.
    <maxTtl> The maximum allowed time-to-live for directives being added to the pool. This can be specified in seconds, minutes, hours, and days, e.g., 120s, 30m, 4h, 2d. Valid units are [smhd]. By default, no maximum is set. A value of "never" specifies that there is no limit.

  • modifyPool

    Modifies the metadata of an existing Cache Pool.

  • Usage:

    hdfs cacheadmin -modifyPool <name> [-owner <owner>] [-group <group>] 
    [-mode <mode>] [-limit <limit>] [-maxTtl <maxTtl>]

    Options:

    Option Description
    <name> The name of the pool to modify.
    <owner> The user name of the owner of the pool.
    <group> The group that the pool is assigned to.
    <mode> The UNIX-style permissions assigned to the pool. Permissions are specified in octal, e.g., 0755.
    <limit> The maximum number of bytes that can be cached by directives in the pool, in aggregate.
    <maxTtl> The maximum allowed time-to-live for directives being added to the pool. This can be specified in seconds, minutes, hours, and days, e.g., 120s, 30m, 4h, 2d. Valid units are [smhd]. A value of "never" specifies that there is no limit.

  • removePool

    Remove a Cache Pool. This also un-caches paths associated with the pool.

    Usage:

    hdfs cacheadmin -removePool <name>

    Options:

    Option Description
    <name> The name of the Cache Pool to remove.

  • listPools

    Displays information about one or more Cache Pools, e.g., name, owner, group, permissions, etc.

    Usage:

    hdfs cacheadmin -listPools [-stats] [<name>]

    Options:

    Option Description
    -stats Display additional Cache Pool statistics.
    <name> If specified, list only the named Cache Pool.

  • help

    Displays detailed information about a command.

    Usage:

    hdfs cacheadmin -help <command-name>

    Options:

    Option Description
    <command-name> Displays detailed information for the specified command name. If no command name is specified, detailed help is displayed for all commands.


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