CFOVER - Coupling Facility Overview Report

The Coupling Facility Overview report (CFOVER) gives you information about all coupling facilities which are connected to the sysplex.

You might start the investigation of the performance of the coupling facilities in your sysplex with the CFOVER report. You get an overview about all coupling facilities showing the utilization of the processors and the storage. If you experience high values for these resources, this might indicate contention in the coupling facilities which could lead to internal queues causing performance problems.

In addition, you can evaluate the request rates to analyze whether the usage of the coupling facilities is well balanced. This, of course, will not be the case if you have one coupling facility for production and the other one just as stand-by.

How to request this report

To request the Coupling Facility Overview report, select S from the Primary Menu and then select 5 on the Sysplex Report menu (shown in Figure 1), or enter the following command: 
CFOVER [cfname]

Contents of the report

Figure 1. CFOVER Report
                    RMF V2R4  CF Overview      - TRXPLEX         Line 1 of 4
Command ===>                                                  Scroll ===> CSR

Samples: 30      Systems: 2    Date: 05/11/19  Time: 08.41.30  Range: 30    Sec

CF Policy: IXCPOLBB    Activated at: 09/14/17 08.31.57

--- Coupling Facility --- ----- Processor -------  Req  - Storage - --- SCM ---
Name     Type Mod Lvl Dyn Util% Def Shr Wgt   Eff  Rate Size  Avail Size  Avail

X7CFH89  2817 E64  16 OFF   0.4   2  0        2.0  68.5   15G   13G    0M    0M
X7CFP87  2827 H66  19 OFF  52.6   2  0        2.0  241K   98G   92G   16G   15G
X7CFP89  2827 HA1  19 ON   12.4   1  0        1.0 412.4  100G   96G  512G  512G
X7CFR89  2817 M80  17 THIN  0.0   2  0  200   1.9   2.0   50G   50G    0M    0M

There is no graphic version of this report available.

Field descriptions

Table 1. Fields in the CFOVER Report
Field Heading Meaning
CF Policy Name of the current coupling facility policy.
Activated at Date and time the current coupling facility policy was activated.
Coupling Facility The following information about the coupling facility is provided:
Name
coupling facility name
Type
coupling facility processor type
Mod
coupling facility processor model
Lvl
coupling facility microcode level
Dyn
Dynamic CF dispatching status (ON, OFF, or THIN). THIN indicates that coupling thin interrupts are enabled for the coupling facility (only for CFLEVEL 19 or higher).
Note: Dynamic CF dispatching is provided by PR/SM and available to all CF partitions with shared engines. It allows the installation to limit the impact of polling for CFs with low activity rates. The amount of CP resource used by the CF is reduced. There is, however, a performance trade-off when working with dynamic dispatching: though the CPU resource consumed by the CF is reduced, the responsiveness of the CF partition is also reduced. In Parallel Sysplex environments with a CFLEVEL 19 or higher, it is recommended to enable coupling thin interrupts for shared-engine coupling facilities.
Processor The following information about the processors within the coupling facility is provided:
Util%
Percentage of processor utilization by the coupling facility.

In case of a stand-alone coupling facility, the utilization of the individual CPs should be approximately the same. In a PR/SM environment where this CP is shared with other partitions, the utilization is the logical utilization of the CP (that is, only the utilization by the coupling facility).

If the utilization is high, you can take the following actions:

  • In a PR/SM environment, you can dedicate the CP to the integrated coupling facility or assign additional CPs to the partition.
  • Move structures to a coupling facility with lower utilization.
  • Consider additional or larger coupling facilities.
Def
Number of logical processors defined for the coupling facility.
Shr
Number of shared processors defined for the coupling facility.
Wgt
Average weight of shared logical processors. This value is not displayed if no shared processors are assigned to this CF.
Eff
Number of effective available logical processors in a shared environment. This value is only useful in a CFCC environment. CFCC measures the time of real command execution as well as the time waiting for work. The reported value shows the ratio of the LPAR dispatch time (CFCC execute and wait time) to the RMF MINTIME length.

For example, if a CFCC CEC contains 6 logical processors, and the measured CF LPAR has two logical processors and is limited at 5%, the number of effective logical processors is 0.3.
Req Rate The sum of all requests (internal and external) that utilize the subchannel. Specifically:
  • External requests to send/receive data on behalf of a structure. The sum of synchronous and asynchronous requests completed against any structure within this coupling facility per second. This includes requests that changed from synchronous to asynchronous.
  • Internal requests that utilize the subchannels (but are not aggregated by the structure).

The value is reported as '< 0.1' if the rate is greater than 0 but would be rounded to 0.
Storage Size The total amount of coupling facility storage in bytes, including both allocated and available space.
Storage Avail The amount of coupling facility space in bytes that is not allocated to any structure, not allocated as dump space, and not allocated as augmented space.
SCM Size The total amount of coupling facility storage class memory in bytes which may be concurrently used as structure extensions.
SCM Avail The total amount of available storage class memory in bytes.