Parallel Writes to Tape

From The Open Source Backup Wiki (Amanda, MySQL Backup, BackupPC)
Jump to navigationJump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

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.

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.