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Cache Subsystem Activity Report

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

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

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

Related topics

CACHE
CACHEACT
Cache-reports

PRODUCED BY CMF ANALYZER (v.r.mm  RSL yymm )                  CACHE SUBSYSTEM ACTIVITY REPORT                      RPTSEQ     4 PAGE     28     
BMC SOFTWARE, INC.                                        BMC SOFTWARE, INC.                            REPORT DATE: DD MMM YY 16.44
REQD 10 JUN YY 09.50.00  10 JUN YY 10.20.00                  HOUSTON, TX.                               SYSTEM ID: SJSE     Z v.rr.n
ACTL 10 JUN YY 09.50.00  10 JUN YY 10.20.00                                                             REPORT CYCLE: CYCLE099       

BASED ON REC TYPE/# RECS/# SAMPLES/REC HOURS:  74-5/24/0/0.5                                                                         

0-------------- 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
1PRODUCED BY CMF ANALYZER (V.R.MM  PUT *UNK*)       CACHE SUBSYSTEM 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
0-------------- SUBSYSTEM ID: 0BC0   CONTROL UNIT: 0BCD   MODEL: 2107-921   MFR: EMC   PLANT: 09   SERIAL: 0000000AWDKL -------------

   DEV  VOLUME  XTNT  ----STATUS---     %     I/O   -CACHE HIT RATE-  --DASD I/O RATE--  ASYNC  -------% HITS------    %
   NUM  SERIAL  POOL  CACHE  DASDFW    I/O   RATE   READ   DFW   CFW  STAGE DLNVS OTHER   RATE  TOTAL   READ  WRITE  READ
 -----  ------  ----  ------ ------  -----  -----  ----- ----- -----  ----- ----- -----  -----  -----  -----  ----- -----
 00BC0  AFXBC0  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BC1  AFXBC1  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BC2  AFXBC2  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BC3  AFXBC3  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BC4  AFXBC4  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BC5  AFXBC5  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BC6  AFXBC6  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BC7  AFXBC7  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BC8  AFXBC8  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.8   66.8      0 100.0
 00BC9  AFXBC9  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BCA  AFXBCA  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BCB  AFXBCB  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BCC  AFXBCC  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BCD  AFXBCD  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BCE  AFXBCE  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BCF  AFXBCF  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BD0  AFXBD0  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BD1  AFXBD1  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BD2  AFXBD2  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BD3  AFXBD3  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.4   66.4      0 100.0
 00BD4  AFXBD4  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BD5  AFX21F  0000  ACTIVE ACTIVE   94.0    7.7    5.2   2.5     0      0     0     0    0.2   99.9   99.9  100.0  67.5
 00BD6  AFXBD6  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.9   66.9      0 100.0
 00BD7  AFXBD7  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BD8  AFXBD8  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.7   66.7      0 100.0
 00BD9  AFXBD9  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BDA  AFXBDA  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.8   66.8      0 100.0
 00BDB  AFXBDB  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BDC  AFXBDC  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.9   66.9      0 100.0
 00BDD  AFXBDD  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   67.0   67.0      0 100.0
 00BDE  AFXBDE  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.8   66.8      0 100.0
 00BDF  AFXBDF  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.8   66.8      0 100.0
 00BE0  AFXBE0  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.9   66.9      0 100.0
 00BE1  AFXBE1  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   67.0   67.0      0 100.0
 00BE2  AFXBE2  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.6   66.6      0 100.0
 00BE3  AFXBE3  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   66.5   66.5      0 100.0
 00BE4  AFXBE4  0000  ACTIVE ACTIVE    0.2      0      0     0     0      0     0     0      0   69.5   69.5      0 100.0

 TOTALS FOR 37 DEVICES:             100.0    8.2    5.5   2.5     0    0.2     0     0     0     0    0.2   97.9   97.0  100.0   69.4


----------------------------------------------------- RAID RANK ACTIVITY -----------------------------------------------------------

                          ---------READ REQUESTS---------   --------WRITE REQUESTS---------                                          
  ID   TYPE     DA   HDD  COUNT  RATE AVG SZ BYTE/S RTIME   COUNT  RATE AVG SZ BYTE/S RTIME  ------ HIGHEST ACTIVITY VOLUMES--------
 ----  -------  --   ---  ----- ----- ------ ------ -----   ----- ----- ------ ------ -----                                          
 0100  RAID-5   11     7     39     0  53.1K  1,151     4     139   0.1  76.3K  5,899    26   FTP109  SMFT03  APD28G  PAGC32  FTP103
 0101  RAID-5   11     7    101   0.1  38.3K  2,150    10       0     0      0      0     0   --A34E  FTP111  FTP112  --A338  --A339

 TOTAL                14    140   0.1  42.4K  3,301     8     139   0.1  76.3K  5,899    26

Cache Subsystem Activity Report field descriptions

The following table describes the fields in the Cache Subsystem 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

Device Overview section

DEV NUM

Five-digit device number that uniquely identifies the DASD device

VOLUME SERIAL

Volume serial number

XTNT POOL or

RRID

ID of the extent pool to which the device belongs (for 2107s and 1750s only)

RAID rank identifier (for systems other than 2107s and 1750s)

STATUS

Cache status of the DASD device:

  • CACHE—caching status
  • DASDFW—DASD Fast Write (DFW) status

% I/O

I/O requests to this DASD volume, as a percentage of all I/O requests to the cache subsystem to which it belongs

I/O RATE

I/O requests per second to the volume

CACHE HIT RATE

I/O requests per second that completed without accessing DASD, by request type:

  • READ—number of READ requests
  • DFW—number of DFW (DASD Fast Write) requests
  • CFW—number of CFW (Cache Fast Write) requests

DASD I/O RATE

I/O requests per second that accessed DASD, by request type:

  • STAGE—normal or sequential requests
  • DLNVS—rate of requests from delayed DFW operations. These operations are delayed due to space constraints for NVS (non-volatile storage).
  • ICL—ICL (Inhibit Cache Load) requests
  • BYP—requests that explicitly bypassed the cache
  • OTHER—requests that were either CFW BYPASS or DFW INHIBIT requests

ASYNC RATE

Number of tracks asynchronously written to the DASD device in order to release space in the cache or NVS storage

A high rate indicates that storage might be over-committed.

% HITS

I/O requests serviced from the cache, as percentages of all I/O requests

TOTAL

Percentage of READ and WRITE requests that were serviced from the cache

READ

Percentage of READ requests that were serviced from the cache

WRITE

Percentage of WRITE requests that were serviced from the cache

READ

READ requests as a percentage of all I/O requests

RAID Rank Activity section (printed only for 2105 subsystems)

ID

RAID rank identifier

TYPE

RAID rank type

DA

Device adapter identifier

HDD

Number of hard disk drives (HDD) in the RAID rank

READ REQUESTS

READ I/O requests:

  • COUNT—number of READ requests
  • RATE—number of READ requests, per second
  • AVG SZ—average number of bytes transferred per READ request
  • BYTE/S—average number of bytes read, per second
  • RTIME—average response time, in milliseconds, to an HDD READ I/O request

WRITE REQUESTS

WRITE I/O requests:

  • COUNT—number of WRITE requests
  • RATE—number of WRITE requests, per second
  • AVG SZ—average number of bytes that were transferred per WRITE request
  • BYTE/S—average number of bytes that were written, per second
  • RTIME—average response time, in milliseconds, to an HDD WRITE I/O request

HIGHEST ACTIVITY VOLUMES

Top five volumes sorted in descending order by I/O activity

 

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