Parallel Writes to Tape

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Amanda can write to multiple volumes in parallel, saving a lot of time.

  • A different dle is sent to each volume.
  • All parts of a DLE are contiguous on a volume, although a DLE on several volumes may not begin at filenum 1 on subsequent volumes.
  • If splitting is enabled and a volume becomes full, the next part of the dle can be on any volume, not necessarily on a new volume.
  • The use of holding disk is still recommended, as it allows more dumps in parallel and many DLEs are not fast enough to stream a tape drive.
  • If a drive is not available at the beginning of the run, amanda will not use it -- it doesn't poll for available drive.

Contents

Advantages

  • Writing to many volume in parallel save times.
  • Can do more than one dump direct to tape in parallel.

Disadvantages

  • Requires a more powerful server to be able to stream multiple drives.
  • Performance can be worse if the server can't stream all the drives.

Requirements

  • A Changer with the new changer API must be used.
  • More than one drive must be defined.

Global Configuration

The taper-parallel-write config option must be set to the number of volume amanda can write to in parallel. There is no other configuration for the feature.

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