Measure Reference Manual

Usage Notes for All DISC Entities
• The DISC counters track all disk activity, including both file activity and internal activities such
as writing to the free space table, writing to the undo area, and writing file and volume labels.
Use the DISC counters to compare and balance the workload of two or more disks.
For information on I/O and caching, see the appropriate system description manual. For
information on TMF auditing and audit trails written to disk, see the TMF Operations and
Recovery Guide.
• Measure does not measure SMF virtual disk processes (VDPs) as DISC entities. For example,
if $V1 is a VDP, the command $ADD DISK $V1 does not collect data for $V1 or for the
physical disks configured under $V1. However, no error is returned.
• SUBSYSTEM-VERSION for ZMSDISC records is provided by DP2.
• DISC reports include fields that are calculated from DISC counters. These fields are not defined
in the DISC DDL record:
DISC-BUSY-TIME
(Legacy Style only) Sum of the DISC WRITE-BUSY-TIME and READ-BUSY-TIME counters.
DISC-RATE
Combined rate of READ and WRITE operations to the physical drive. This value is included
in the BRIEF format report.
Counter type: Incrementing.
REQUEST-ART
(ZMS Style only) Average time that each request spends waiting or being processed by
DP2. REQUEST-QTIME is divided by REQUESTS.
Counter type: Response time.
DEVICE-AST
(ZMS Style only) Average time that each request spends waiting or being processed by
DP2. DEVICE-QBUSY-TIME is divided by the sum of READS and WRITES.
Counter type: Service time.
Usage Notes for H-Series and J-Series DISC Entities
• For CLIM-attached devices in H06.23/J06.12 and later RVUs, the DISC entity specification
is updated to include partition as an optional parameter. This entity specification can be
used in the ADD, DELETE, LIST, LISTACTIVE, and LISTALL commands. In addition, the partition
number will be displayed in the INFO and INFO MEASUREMENT commands if partition
was specified for the measurement.
• For CLIM-attached devices in Measure H03/J01 and later PVUs, the DISC entity specification
is updated to include lun and path and to not use scsi-id. As with FCSA devices, this
entity specification can be used in the ADD, DELETE, LIST, LISTACTIVE, and LISTALL commands.
• In H-series and J-series RVUs, all byte-count fields have 64 bits. Field names ending in -F are
no longer used in ZMS style but remain available to applications that request data in legacy
style.
Usage Notes for G-Series DISC Entities
• To measure device-busy time, use the DEVICE-QBUSY-TIME counter. DEVICE-QBUSY-TIME is
a replacement for the D-series field DISC-BUSY-TIME.
In D-series RVUs, DISC-BUSY-TIME is calculated by adding the values of the DISC
WRITE-BUSY-TIME and READ-BUSY-TIME counters. However, in G-series RVUs,
DEVICE-QBUSY-TIME does not equal WRITE-QBUSY-TIME plus READ-QBUSY-TIME. In the
206 Entities and Counters