DEVICE DISK report

This report contains data on the I/O operations performed with peripheral devices during one monitoring cycle. It counts the number of EXCP calls per second (see also “glossary”, “EXCP“).

Report output

The REPORT DEVICE_DISK statement allows the user to request the output of the DEVICE DISK report.

The monitored data under SERVICETIME is only output if the SM2 administrator:

• uses the SET-SAMPLING-DEVICE-PARAMETERS statement to define the monitoring of the service times and

• uses the START-MEASUREMENT-PROGRAM TYPE=*SAMPLING-DEVICE statement to start monitoring.

When the SM2 subsystem is started, the SAMPLING-DEVICE monitoring program is started without the service times being recorded.

Overflow screens can be requested for this report.

The output of the monitored data is sorted on the basis of the sort criterion. The sort criterion is defined by means of the SELECT-DEVICE-DISK-PARAMETERS statement. Sorting on the basis of the sum of READ (IO/S) and WRITE (IO/S) is specified by default.

SM2 is not notified of device management commands (see the “Commands” manual [3]). In the monitoring cycle in which such commands are entered, incorrect data may be produced for the affected devices.

For parallel access volumes (PAV), the following applies:

Only base devices are output. The monitored data refers to the base device and the assigned alias devices.

For information on PAV see the “Introduction to System Administration” manual [6].

HOST0001 SM2 DEVICE DISK (I) CYCLE:   60 S  SAMPLES:   150      <date> <time> 

  MN |VOLUME|  Q |   RUN   |     READ      |    WRITE      |  SERVICETIME       
     |      |LGTH| TOT| PG |(IO/S)| (KB/S) |(IO/S)| (KB/S) |HW (MS)|SW (MS)     
 ----+------+----+----+----+------+--------+------+--------+-------+-------     
 8037|SE10.5| 4.8| 4.2| 0.0|4990.9|  9982.8| 680.8|  1361.6|  0.645|  0.765     
 8035|SE10.3| 4.7| 3.5| 0.0|4651.2|  9302.9| 562.3|  1124.7|  0.633|  0.741     
 8036|SE10.4| 4.8| 3.8| 0.0|4632.8|  9266.3| 567.2|  1134.5|  0.678|  0.824     
 8034|SE10.2| 5.8| 4.2| 0.0|3426.1|  6852.5| 992.3|  1984.8|  1.223|  1.457     

Monitoring information

In addition to the name of the report, the sort criterion is also output in the header: I (IO), Q (QLENGTH), R (RUNIO) or S (SWTIME).

MN	Mnemonic name of the disk device
VOLUME	VSN of the disk device or spaces (e.g. when the disk belongs to a pubset that has not been imported)
Q-LGTH	Average length of the device queue, including jobs currently being serviced
RUN
TOT	Average number of parallel processed inputs/outputs
PG	Average number of parallel processed paging inputs/outputs
READ	Number of input operations or number of KB transferred per second
WRITE	Number of output operations or number of KB transferred per second
SERVICETIME
HW (MS)	Average hardware service time in milliseconds
SW (MS)	Average software service time (including hardware service time) in milliseconds