RTDMOUNTTIME and VTVMOUNTTIME Statements (Optional)
The RTDMOUNTTIME and VTVMOUNTTIME statements apply to units processing StorageTek VSM data, and define seven mount time threshold limits that are used for real tape (RTDMOUNTTIME) and virtual tape (VTVMOUNTTIME) mount time distribution calculations.
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RTDMOUNTTIME Statement
The RTDMOUNTTIME statement format is:
RTDMOUNTTIME limit1 limit2 limit3 limit4 limit5 limit6 limit7
limit1-limit7
Each mount time threshold limit is defined in seconds. It can be one to four digits, with a maximum value of 3600. Subsecond mount time limits are coded in the form
.nnn
, although subsecond mount times do not generally apply to real tape drives. The limits can be separated by one or more blanks.Default RTDMOUNTTIME statement:
RTDMOUNTTIME 5 10 30 60 120 180 240
With the above real tape drive mount time limits, the TLM component accumulates mount distribution counters for each real tape drive mount, as illustrated in the following table:
(SVTRDSTx) (RMRMTM) mount counter 1: 0 < mount <= 5 mount counter 2: 5 < mount <= 10 mount counter 3: 10 < mount <= 30 mount counter 4: 30 < mount <= 60 mount counter 5: 60 < mount <= 120 mount counter 6: 120 < mount <= 180 mount counter 7: 180 < mount <= 240 mount counter 8: 240 < mount
Note:
The VTS component creates an eighth counter to capture all mount events that are greater than limit7 as defined by the RTDMOUNTTIME statement.VTVMOUNTTIME Statement
The VTVMOUNTTIME statement format is:
VTVMOUNTTIME limit1 limit2 limit3 limit4 limit5 limit6 limit7
limit1-limit7
Each mount time threshold limit is defined in seconds. It can be one to four digits, with a maximum value of 3600. Subsecond mount time limits are coded in the form
.nnn
. The limits can be separated by one or more blanks.Default VTVMOUNTTIME statement:
VTVMOUNTTIME .5 1 2 5 30 60 120
With the above virtual tape drive mount time limits, the VTS component accumulates mount distribution counters for each virtual mount, as illustrated in the following table:
(SVTVDSTx) (VMRMTM) mount counter 1: 0 < mount <= 0.50 mount counter 2: 0.50 < mount <= 1 mount counter 3: 1 < mount <= 5 mount counter 4: 5 < mount <= 10 mount counter 5: 10 < mount <= 30 mount counter 6: 30 < mount <= 60 mount counter 7: 60 < mount <= 120 mount counter 8: 120 < mount
Note:
The VTS component creates an eighth counter to capture all mount events that are greater than limit7 as defined by the VTVMOUNTTIME statement.Tracking mount time distributions can be very useful. The majority of both real and virtual tape mount times tend to be clustered in one to three buckets that represent normal performance. If the count of mounts in the higher buckets is greater during certain hours, there might be an opportunity for workload shifting to alleviate resource contention.
Shifting of the general distribution of mount times toward the higher buckets might signify that the general workload has exceeded the capacity of the existing virtual tape systems.