StorageTek Host Software Component 6.0, System Programmer'S Manual

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414 VM/HSC 6.0 System Programmer’s Guide
1st ed., 6/30/04 - 312579601
Redistribute Scratch Volumes in the Library
The Scratch Redistribution utility allows you to redistribute scratch volumes across the
LSMs within a particular ACS. You can choose to have the scratch volumes go to only
specified LSMs or all LSMs within an ACS.
Redistribution is performed to an evenness defined by the balance tolerance level which is
specified via the Scratch Redistribution utility. If necessary, the Scratch Redistribution
utility swaps scratch volumes with nonscratch volumes to equalize the count of scratch
cartridges in an ACS.
Refer to Chapter 4, “Utility Functions” on page 169 for detailed information on the
Scratch Redistribution utility, syntax, and parameters.
Maintain Quantities of Scratch Cartridges
Typically, in a high-activity environment, if there are insufficient quantities of scratch
volumes available within a library, production time can be lost. Scratch volumes are
maintained in scratch pools that are defined across the library LSMs. It is important that
the number of cartridges maintained in the scratch pools are sufficient enough for normal
library operation at your data center. The operator or the systems programmer can control
when the HSC warns of low quantities of scratch cartridges.
The Warn command establishes thresholds which control when the HSC notifies the
operator of an insufficient quantity of scratch cartridges in an ACS. The scratch pool
depletion warning notifies the operator when the number of scratch volumes in an ACS
falls below a specified minimum value.
By specifying warning thresholds, you can know when the number of scratch cartridges is
too low for normal library operation.
Refer to the HSC Operator’s Guide for more information about the command, syntax, and
parameters.
Define CAP Preferences
The physical configuration of your library, especially the location of CAPs, can affect both
library performance and operator performance. For a more efficient operation, ideally the
operator should be located close to the CAPs being used the most. You can control which
CAPs are most used.
The CAP preference (CAPPref) command enables you to specify preference values for
CAPs. If CAP preferences are not specified, the CAP preference value is set to zero. A
CAP with a preference value of zero is never selected (defaulted to) by the HSC unless
specifically requested. The CAP preference list specified in the command establishes an
ordered list of CAPs for use during cartridge entry and ejection. The HSC chooses an
available CAP from this list by starting at the highest priority and moving down the list
until a nonbusy, nonzero-priority CAP is identified.