Measure Reference Manual

Legacy Style Only Counter Field DDL Definitions for CONTROLLER Entities
These counter fields are used in Legacy Style DDL records only.
Fields are listed alphabetically.
IO-QLEN-MAX
Maximum number of outstanding I/Os on the controller queue described by the IO-QTIME counter.
Counter type: Max queue.
IO-QTIME
Time that the controller is busy performing I/Os. If the average number of I/Os is less than 1, the
number can be interpreted as the controller busy percentage.
Counter type: Queue.
REQUESTS
Total number of requests to the controller by all I/O processes (IOPs) connected to this controller
path.
Counter type: Incrementing.
TOTAL-IO-BYTES
Total number of bytes transferred to and from the controller by all IOPs connected to this controller
path.
Counter type: Accumulating.
Usage Notes for CONTROLLER Entities
• Because of differences in implementation, CONTROLLER counters are not directly comparable
to device-level counters. For example, a CONTROLLER REQUESTS counter value is not equal
to the sum of the REQUESTS counter values for all devices that share that controller.
• Measuring controller activity has questionable usefulness and is NOT generally advised.
Architectural differences between the communication and disk subsystems preclude correct
data being collected for communication devices. In addition, compatibility problems between
controller entity measurements and the online configuration utility program (COUP) can cause
serious system stability issues (for example, system halts). Therefore, do not use the
CONTROLLER entity with COUP.
• The requests and data bytes returned from storage controllers are valid and can potentially
be useful in assessing system performance. To enable the CONTROLLER entity in a test
environment, set the define outlined in CONTROLLER (page 158).
160 Entities and Counters