StorageTek Host Software Component 6.0, Руководство системного программиста

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426 VM/HSC 6.0 System Programmer’s Guide
1st ed., 6/30/04 - 312579601
DETACHed from a virtual machine. This enables the volume to be available (that is,
unselected) earlier than would otherwise be possible.
ACSPROP EXEC can also be used with VMOPERATOR to trap MOUNT messages for
VMTAPE. LOGTABLE SAMPLE contains sample VMOPERATOR LOGTABLE
statements to assist you. Consult VMOPERATOR documentation for information about
tailoring the samples to your needs.
Syntax
Parameters
There are no external parameters required. The PROP interface to an EXEC action routine
provides parameters in the program stack. These are documented in the VM description of
PROP.
Usage Requirements
The only requirement is that the PROP ‘logical operator’ have a link to the MAINTSTK
RUN-disk.
Reduce Scheduling Contention
Effective scheduling can increase library performance. Controlling the following
scheduling related areas can help significantly in further increasing library performance:
• strive for a balanced workload
• schedule nonproductive library activities during low-demand times.
Balancing the Workload
If you experience higher than expected average mount times, but at the same time
experience an improvement in production through-put, it could be an indication that
your system is periodically flooded with work rather than having a balanced
workload.
For example, all of your production jobs may be getting submitted at the beginning
of a shift so that the library robots are overworked for the first few hours of the shift.
Then, the robots may remain idle for the remainder of the shift. If you are using a
scheduling software package and it releases jobs every hour on the hour, there may
be tremendous tape transport contention for the first few minutes of each hour while
the transports are unused for the remainder of each hour.
These situations tend to elevate average mount times; however, as long as the work is
performed on time, there is probably no need to change conditions. However, if the
work is not getting performed on schedule, you can improve performance by
balancing your production workload.
EXEC
ACSPROP