Cache Device Activity Report

This report is produced by the CACHEACT Analyzer control statement when REPORT=DEVICE is specified.

By default, the report is ordered by subsystem ID/device ID, but the order can be changed by the ORDER= parameter. The report can be filtered by model, subsystem ID, device ID, and a threshold value. Specific subsystems or devices can be selected or excluded.

The following figure shows an example of the Cache Device Activity Report:

Related topics

CACHE
CACHEACT
Cache-reports

PRODUCED BY CMF ANALYZER (V.R.MM PUT *UNK*)         CACHE DEVICE ACTIVITY REPORT                       RPTSEQ     3 PAGE      6
BMC Software, Inc.                                         BMC SOFTWARE, INC.                           REPORT DATE: 01 JAN 20 12.00
ACTL 16 DEC 19 21.35.29 17 DEC 19 18.30.00                   HOUSTON, TX.                              SYSTEM ID: SJSC     Z 2.04.0

BASED ON REC TYPE/# RECS/# SAMPLES/REC HOURS: 74-5/9,520/0/20.91
-------------- SUBSYSTEM ID: 0BC0   CONTROL UNIT: 0BCD   MODEL: 2107-921   MFR: EMC   PLANT: 09   SERIAL: 0000000AWDKL -------------

   SUBSYSTEM STORAGE       NON-VOLATILE STORAGE        S U B S Y S T E M     S T A T U S         I/O TOTALS              HIT %
---------------------- -------------------------   ---------------------------------------   ----------------      ----------------
CONFIGURED       366GB CONFIGURED          192MB   NON-VOLATILE STORAGE - ACTIVE             CACHE    618,798      CACHE       97.9
AVAILABLE        366GB PINNED                  0   CACHE FAST WRITE     - DEACTIVATED        TOTAL    618,798      TOTAL       97.9
PINNED               0
OFFLINE              0

CACHE I/O    -------------READ I/O REQUESTS-------------     ----------------------WRITE I/O REQUESTS----------------------       %
REQUESTS       COUNT     RATE      HITS     RATE   HIT %       COUNT     RATE      FAST     RATE       HITS    RATE   HIT %     READ

NORMAL       404,180      5.4   404,107      5.4   100.0     189,304      2.5   189,304      2.5    189,303     2.5   100.0     68.1
SEQUENTIAL    25,314      0.3    12,656      0.2    50.0           0        0         0        0          0       0       0    100.0
CFW DATA           0        0         0        0       0           0        0         0        0          0       0       0        0

TOTAL        429,494      5.7   416,763      5.5    97.0     189,304      2.5   189,304      2.5    189,303     2.5   100.0     69.4

-----------------------CACHE MISSES-----------------------            ------------MISC------------
REQUESTS      READ    RATE   WRITE    RATE TRACKS    RATE                            COUNT   RATE

NORMAL          73       0       1       0       0       0            DELAYED NVS         0      0
SEQUENTIAL 12,658     0.2       0       0       4       0            DELAYED CACHE       0      0
CFW DATA         0       0       0       0                            DFW INHIBIT         0      0
                                                                       ASYNC (TRKS)   15,452    0.2
TOTAL CACHE MISSES   12,732   RATE    0.17
TOTAL CACHE HITS    618,798   RATE    8.23                            --------DISK ACTIVITY-------         --HOST ADAPTER ACTIVITY--
                                                                               RESP   BYTES BYTES                     BYTES   BYTES
---CKD STATISTICS---     ---RECORD CACHING---                                  TIME    /REQ   /SEC                      /REQ    /SEC
                                                                      READ        0       0      0         READ        3,963 22,629
WRITE          1,052     READ MISSES        0                         WRITE       0       0      0         WRITE       4,127 10,386
WRITE HITS     1,052     WRITE PROM         0
PRODUCED BY CMF ANALYZER (V.R.MM PUT *UNK*)         CACHE DEVICE ACTIVITY REPORT                       RPTSEQ     3 PAGE      7
BMC Software, Inc.                                              BCM1409                                 REPORT DATE: 01 JAN 20 12.00
ACTL 16 DEC 19 21.35.29 17 DEC 19 18.30.00             z/OS 2.4 Cache Activity                         SYSTEM ID: SJSC     Z 2.04.0

BASED ON REC TYPE/# RECS/# SAMPLES/REC HOURS: 74-5/9,520/0/20.91
VOLSER: AFXBC0   DEVICE: 00BC0   XTNT POOL: 0000   SUBSYSTEM ID: 0BC0   MODEL: 2107-921 MFR: EMC   PLANT: 09   SERIAL: 0000000AWDKL

      C A C H E    S T A T U S                      I/O TOTALS            HIT %
-------------------------------------------     -----------------   ----------------
DASD FAST WRITE - ACTIVE                        CACHE       1,044   CACHE       66.5
PINNED DATA     - NONE                          TOTAL       1,044   TOTAL       66.5

CACHE I/O    -------------READ I/O REQUESTS-------------     ----------------------WRITE I/O REQUESTS----------------------       %
REQUESTS       COUNT     RATE      HITS     RATE   HIT %       COUNT     RATE      FAST     RATE       HITS    RATE   HIT %     READ

NORMAL           344        0       344        0   100.0           0        0         0        0          0       0       0    100.0
SEQUENTIAL       700        0       350        0    50.0           0        0         0        0          0       0       0    100.0
CFW DATA           0        0         0        0       0           0        0         0        0          0       0       0        0

TOTAL          1,044        0       694        0    66.5           0        0         0        0          0       0       0    100.0

-----------------------CACHE MISSES-----------------------            ------------MISC------------
REQUESTS      READ    RATE   WRITE    RATE TRACKS    RATE                            COUNT   RATE

NORMAL           0       0       0       0       0       0            DELAYED NVS         0      0
SEQUENTIAL     350       0       0       0       0       0            DELAYED CACHE       0      0
CFW DATA         0       0       0       0                            DFW INHIBIT         0      0
                                                                      ASYNC (TRKS)        0      0
                                                                      ASYNC (TRKS)        0      0
TOTAL CACHE MISSES      350   RATE       0
TOTAL CACHE HITS      1,044   RATE    0.01                            --------DISK ACTIVITY-------         --HOST ADAPTER ACTIVITY--
                                                                               RESP   BYTES BYTES                     BYTES   BYTES
---CKD STATISTICS---     ---RECORD CACHING---                                  TIME    /REQ   /SEC                      /REQ    /SEC
                                                                      READ        0       0      0         READ        2,260      31
WRITE             27     READ MISSES        0                         WRITE       0       0      0         WRITE           0       0
WRITE HITS        27     WRITE PROM         0

Cache Device Activity Report field descriptions

The Cache Device Activity Report consists of the following sections and fields:

The first page, for each subsystem, is the same as the first page of the Cache Subsystem Activity report. The fields in that report are described in Cache Subsystem Activity Report field descriptions.
The following pages, for each subsystem, contain device detail information, one page per device, for each device in the subsystem. This page consists of two sections: a status section and an activity section. The activity section uses the same format as the first page of the Cache Subsystem Activity Report, except that it is for activity that is specific to the device.

The following table describes the fields in the status section of the Cache Device Activity Report:

Field	Description
Subsystem Status section
SUBSYSTEM ID	Physical control unit number of the cache subsystem
MODEL	Hardware model ID
Control UNIT	Physical control unit number of the caching subsystem; this number is equal to the lowest device number for the subsystem
MFR	Manufacturer code of the cache subsystem
PLANT	Plant code of the cache subsystem
SERIAL	Serial number of the cache subsystem
SUBSYSTEM STORAGE	Cache storage status, in megabytes: CONFIGURED—amount installed AVAILABLE—amount available PINNED—amount pinned in cache - DASD failure prevents data destaging OFFLINE—amount offline, possibly due to error
NON-VOLATILE STORAGE	Nonvolatile storage (NVS) status, in megabytes: CONFIGURED—amount installed PINNED—amount pinned in NVS - DASD failure prevents data destaging
SUBSYSTEM STATUS	Caching status of the entire subsystem: NON-VOLATILE STORAGE ACTIVE—NVS caching is online and usable INTERNAL ERROR—internal error stopped NVS cache HOST TERMINATION—host deactivated NVS caching DFW SUSPENDED—DFW inhibited - battery failure PENDING OFFLINE—NVS cache deactivation pending IN MAINTENANCE—NVS disabled for maintenance ?????—unknown status CACHE FAST WRITE ACTIVE—CFW is active DEACTIVATED—CFW has been deactivated
I/O TOTALS	Number of I/O requests: CACHE—cacheable I/O requests to cached devices OFFLINE—I/O requests to non-cached devices NONCACHE—sum of INHIBIT CACHE LOAD and CACHE BYPASS requests TOTAL—sum of all I/O requests
HIT %	Cache hits, as percentages of all I/O requests: CACHE—percentage of cacheable I/O requests that were serviced from cache TOTAL—percentage of all I/O requests that were serviced from cache
Subsystem Details section
CACHE I/O REQUESTS	Specified by the DEFINE EXTENT command; categorizes the way cache is managed, as one of three classes: NORMAL—use the normal LRU algorithm to make cache space available SEQUENTIAL—preload of tracks from DASD for sequential I/O requests CFW DATA—handle WRITE and READ-AFTER-WRITE requests in cache TOTAL—totals or averages for the three defined classes
READ I/O REQUESTS	I/O requests that had at least one SEARCH or READ command and no WRITE command; only requests to cached devices are counted: COUNT—total number of SEARCH/READ requests RATE—SEARCH/READ requests per second HITS—SEARCH/READ requests handled without accessing DASD RATE—SEARCH/READ requests handled without accessing DASD, per second HIT %—SEARCH/READ cache hits, as a percentage of all such requests
WRITE I/O REQUESTS	I/O requests that had at least one WRITE command; only requests to cached devices are counted: COUNT—total number of WRITE requests RATE—WRITE requests per second FAST—CACHE/DASD FAST WRITE (CFW and DFW) requests RATE—CFW/DFW requests per second HITS—CFW/DFW requests handled without accessing DASD RATE—CFW/DFW requests processed without accessing DASD, per second HIT %—CFW/DFW cache hits, as a percentage of all WRITE requests
% READ	READ requests as a percentage of all READ and WRITE requests
CACHE MISSES	Occurs under the following situations: Data to be read or written is not found in the cache. This problem causes the track or tracks containing the data to be read from DASD and placed in the cache. A lack of NVS storage causes the data to be written to DASD immediately. For some reason, DASD FAST WRITE (DFW) is inhibited. Possible values are: READ—SEARCH/READ requests that accessed DASD RATE—SEARCH/READ requests that accessed DASD, per second WRITE—WRITE requests that accessed DASD RATE—WRITE requests that accessed DASD, per second TRACKS—number of tracks transferred from DASD to cache RATE—number of tracks transferred from DASD to cache, per second
MISC	Miscellaneous I/O requests DELAYED DUE TO NVS—DASD Fast Write operations delayed due to non-volatile storage space constraints DELAYED DUE TO CACHE—operations delayed due to cache space constraints DFW INHIBIT ASYNC (TRKS)
DFW INHIBIT	If DASD FAST WRITE (DFW) is active, the number of WRITE requests that inhibited DFW If DFW is inactive, the number of WRITE requests that directly accessed the DASD is recorded in this field. COUNT—total number of DFW INHIBIT requests RATE—DFW INHIBIT requests per second
ASYNC (TRKS)	Number of tracks asynchronously transferred from cache to DASD, in order to free space in the cache and the NVS For a duplex pair, this figure is the number of transfers from the primary cache to the secondary. A high number of ASYNC I/Os indicates an over-committed cache or NVS. COUNT—number of tracks asynchronously transferred from cache to DASD RATE—number of tracks asynchronously transferred, per second
ICL	Inhibit cache load (ICL) Number of I/O requests that inhibited the loading of data into cache, even though the data was not found in the cache. COUNT—total number of ICL requests RATE—ICL requests per second
BYPASS	Number of I/O requests that explicitly bypassed the cache, whether or not the data was in the cache: COUNT—total number of BYPASS requests RATE—BYPASS requests per second
TOTAL	Total number of I/O requests that bypassed the cache: COUNT—number of I/O requests that bypassed the cache RATE—number of I/O requests that bypassed the cache, per second
TOTAL CACHE MISSES	Count and rate of I/O requests that were not serviced from cache
TOTAL CACHE HITS	Count and rate of I/O requests that were serviced from cache
SYNCH I/O ACTIVITY	Synchronous I/O activity for cache devices and subsystems The report produces this section if the following conditions are met: Synchronous I/O activity is detected in an interval You request the Subsystem and Device reports
DISK ACTIVITY	Transfer activity from hard disk to cache and vice versa This information is available only for 2107 and 1750 subsystems; for all other subsystems, dashes will print in place of the missing data.
HOST ADAPTER ACTIVITY	I/O activity of normal, sequential, and CFW read and write requests This information is available only for 2107 and 1750 subsystems; for all other subsystems, dashes will print in place of the missing data.
RESP TIME	Response time in milliseconds per read and write request
BYTES/REQ	Average number of bytes transferred per read and write requests
BYTES/SEC	Average number of bytes transferred per second per read and write requests
CKD STATISTICS	Count-Key-Data (CKD) track format requests: WRITE—number of CKD WRITE requests (also in total WRITE count) WRITE HITS—CKD WRITE requests that were handled in cache
RECORD CACHING	Dynamic record caching counts; normally, only whole tracks are cached: READ MISSES—count of records to be read that were not in the cache WRITE PROM—count of records to be written that needed to access DASD

Cache Device Activity Report

Cache Device Activity Report field descriptions

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