How To:Write to Multiple Volumes in Parallel: Difference between revisions
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* A changer with the new [[changer API]] must be used. | * A changer with the new [[changer API]] must be used. | ||
* The changer must provide more than one drive | * The changer must provide more than one drive | ||
How | * Spanning should be set up (see [[How To:Split Dumps Across Tapes]]), although this is not strictly required. | ||
Only some changers support multiple drives: | |||
* chg-disk: Nothing to do, an infinite number of drive is already available. | * chg-disk: Nothing to do, an infinite number of drive is already available. | ||
* chg-multi: Nothing to do, all drives are already defined. | * chg-multi: Nothing to do, all drives are already defined. | ||
Revision as of 23:23, 28 September 2010
Amanda supports parallel writes to tape, meaning that the Amanda server can send multiple DLEs to different volumes at the same time. This is useful if you write to more than one volume in a run and the changer have more than one drive.
Requirements
- A changer with the new changer API must be used.
- The changer must provide more than one drive
- Spanning should be set up (see How To:Split Dumps Across Tapes), although this is not strictly required.
Only some changers support multiple drives:
- chg-disk: Nothing to do, an infinite number of drive is already available.
- chg-multi: Nothing to do, all drives are already defined.
- chg-ndmp: Define all drives with the tape-device property.
- chg-robot: Define all drives with the tape-device property.
- chg-single: Impossible to do, only one drive is available.
Configuration
Only one amanda.conf(5) parameter affects parallel writes:
taper-parallel-write 2
the number gives the maximum number of parallel writes that are allowed.
Examples
- chg-disk
taper-parallel-write 2 tpchanger "chg-disk:/path/to/vtapes"
- chg-robot
taper-parallel-write 2
define changer hp-robot {
tapedev "chg-robot:/dev/sg1"
property "tape-device" "0=tape:/dev/nst0"
property append "tape-device" "1=tape:/dev/nst1"
}
tpchanger "hp-robot"
Note that, for the chg-robot configuration, the taper-parallel-write parameter must be less than or equal to the number of drives configured with the TAPE-DEVICE property.