StorageTek Host Software Component 6 User Manual

1st ed., 6/30/04 - 312579601

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. 

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. 

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.