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This report produces a tabular listing of cache usage on
3880-23 and 3990-3 control units by VOLSER for the duration
of the period specified in the run-time execution parameters.
The report is in two formats: one for 3880-23 controllers,
and one for 3990-3 controllers. These are identified by the
report titles.
INTENDED USE:
For analysis of cache usage in terms of how much activity
is directed to cache VOLSERs; whether transfers to and
from DASD are being avoided by using cache; and what
percentage of bytes read are from cache, from DASD
bypassing cache, and from DASD due to read misses. This
report can be used to detect when cache is being utilized
inefficiently, and for monitoring changes to the cache
environment.
FORMAT 3880-23 Control Units:
A tabular report in ascending order of device address
where each column represents a different measurement
associated with a given VOLSER:
READ HIT RATIO - The ratio of the sum of all "search
and read normal" and "search and read sequential"
requests that were satisfied from cache to the total
number of read requests to the volume.
WRITE/READ RATIO - The ratio of the sum of all "write
normal" and "write sequential" requests to the sum of
all "search and read normal" and "search and read
sequential" requests.
READ REQUESTS - The sum of all "search and read
normal" and "search and read sequential" requests to
the volume.
WRITE REQUESTS - the sum of all "write normal" and
"write sequential" requests.
PCT OF DASD READ CACHE - The percentage of all bytes
transferred from this VOLSER that were transferred
from cache to the channel without DASD access.
PCT OF DASD READ DASD - The percentage of all bytes
transferred from this VOLSER that were transferred
from DASD to cache to the channel due to read misses.
PCT OF DASD READ BYPASS - The percentage of all bytes
transferred from this VOLSER that were transferred
from DASD to the channel, bypassing cache access.
FORMAT 3990-3 Control Units:
A tabular report in ascending order of device address
where each column represents a different measurement
associated with a given VOLSER:
OVERALL READ HIT RATIO - The ratio of the sum of all
basic and extended function read requests that were
satisfied from cache to the total number of read
requests for the volume.
OVERALL WRITE/READ RATIO - The ratio of the sum of
all write requests to the sum of all read requests
for the volume.
BASIC READ HIT RATIO - The ratio of basic read
(search and read normal, and search and read
sequential) requests satisfied from cache to basic
read requests for the volume.
BASIC READ WRITE RATIO - The ratio of basic read
requests and basic write requests for the volume.
DASD F/W HIT RATIO - The ratio of DASD Fast Write
requests that replaced a record in cache to the total
of all DASD Fast Write requests for the volume.
DASD F/W OVERFLOW RATE - The rate at which DASD Fast
Write requests had to be directed to DASD because
cache was not available due to capacity constraints.
CACHE F/W READ HIT RATIO - The ratio of Cache Fast
Write read requests satisfied from cache to the
number of Cache Fast Write read requests made.
CACHE F/W WRITE HIT RATIO - The ratio of Cache Fast
Write write requests satisfied from cache to the
number of Cache Fast Write write requests made.
An example of the report for FORMAT 3880-23 Control Units
is shown in Figure 3-15.
An example of the report for FORMAT 3990-3 Control Units
is shown in Figure 3-16.
INQUIRY ID:
Tabular Report: VMXTX1
DATA SOURCE (File/Timespan):
VMXCDI01 - DETAIL
DATA ELEMENTS USED:
VMXDVSID - Host Subchannel ID
CDISRNRQ - Search and Read Normal Requests
CDISRSRQ - Search and Read Sequential Requests
CDISRNRH - Search and Read Normal Request Hits
CDISRSRH - Search and Read Sequential Request Hits
CDIWNRQ - Write Normal Requests
CDIWSQRQ - Write Sequential Requests
CDIDACBX - Bytes Transferred From DASD To Channel
CDICACBX - Bytes Transferred From Cache To Channel
CDIDCCBX - Bytes Xfr From DASD To Cache and Channel
CDIDFWNO - DASD Fast Write Normal Requests
CDIDFWSO - DASD Fast Write Sequential Requests
CDIDFWRH - DASD Fast Write Normal Request Hits
CDIFWSRH - DASD Fast Write Sequential Request Hits
CDISRCRQ - Cache Fast Write Read Requests
CDISRCRH - Cache Fast Write Read Request Hits
CDIDFWRH - DASD Fast Write Normal Request Hits
CDIFWSRH - DASD Fast Write Sequential Request Hits
CALCULATIONS:
A number of elements are calculated in arriving at this
report, as follows:
READREQ = CDISRNRQ + CDISRSRQ;
WRITEREQ = CDIWNRQ + CDIWSQRQ;
IF READREQ > 0 THEN DO;
RHRATIO = 100 * ((CDISRNRH + CDISRSRH) / READREQ);
WRRATIO = 100 * (WRITEREQ / READREQ);
END;
ELSE DO;
RHRATIO = 0;
WRRATIO = 0;
END;
BYTEXFRD = SUM(CDIDACBX,CDICACBX,CDIDCCBX);
IF BYTEXFRD > 0 THEN DO;
CACHE = 100 * (CDICACBX / BYTEXFRD);
DASD = 100 * (CDIDCCBX / BYTEXFRD);
BYPASS = 100 * (CDIDACBX / BYTESFRD);
END;
ELSE DO;
CACHE = 0; DASD = 0; BYPASS = 0;
END;
USAGE CONSIDERATIONS: None
------------------------------------------------------------------------------------------------------------------------------------ Detail VM Cache Usage Report CA Production Complex INQUIRY: VMXTX1 RUN DATE: 14DECyy System: VMXA Date: 13DECyy Control Unit Type: 3880-23 Time: 12:00 ------------------------------------------------------------------------------------------------------------------------------------ Read Write Percent Of Read I/Os Device Hit Read Read Write -------------------- VOLSER Number Ratio Ratio Requests Requests Cache DASD Bypass ------------------------------------------------------------------------------------------------------------------------------------ MVSC1A 0977 97.79 87.99 6,605 5,812 98.30 1.67 0.02 MVSDL1 0976 71.43 0.00 28 0 68.38 30.78 0.84 MVS006 0960 95.48 0.58 9,588 56 94.40 5.49 0.11 MVS007 0962 98.44 10.74 26,484 2,845 99.92 0.07 0.00 MVS042 0964 84.54 2.06 22,767 468 81.89 13.65 4.46 MVS043 0975 89.72 1.72 17,828 307 79.51 17.86 2.63 MVS961 0961 86.16 7.56 4,284 324 75.30 21.64 3.06 MVS963 0963 96.57 11.97 95,654 11,453 94.49 5.35 0.16 MVS965 0965 91.29 83.71 1,136 951 75.29 20.12 4.59 MVS966 0966 85.33 7.33 1,500 110 83.29 14.78 1.93 MVS967 0967 86.93 27.37 8,136 2,227 87.07 12.01 0.91 MVS970 0970 95.71 0.03 6,670 2 77.96 21.26 0.78 MVS971 0971 50.35 1.23 5,295 65 88.20 10.83 0.97 MVS972 0972 92.00 39.74 9,925 3,944 89.74 10.08 0.18 MVS973 0973 95.13 0.83 58,255 486 91.04 8.71 0.25 MXARS1 0974 75.88 0.00 879 0 65.93 31.21 2.86 ------------------------------------------------------------------------------------------------------------------------------------
Figure 3-15. Detail VM 3880-23 Cache Usage Report
------------------------------------------------------------------------------------------------------------------------------------ Detail VM Cache Usage Report CA Production Complex INQUIRY: VMXTX1 RUN DATE: 14DECyy System: VMXA Date: 13DECyy Control Unit Type: 3990-3 Time: 12:00 ------------------------------------------------------------------------------------------------------------------------------------ <--- Overall ---><---- Basic ---> <-- DASD F/W --> <-- Cache F/W --> Device Read Hit R/Write Read Hit R/Write Read Hit Overflow Read Hit Write Hit VOLSER Number Ratio Ratio Ratio Ratio Ratio Rate Ratio Ratio ------------------------------------------------------------------------------------------------------------------------------------ HSM008 08C8 73.15 0.00 73.15 0.00 0.00 0.00 0.00 0.00 LRG009 08C9 99.66 116.10 99.66 116.10 0.00 0.00 0.00 0.00 LRG010 08CA 92.49 5.38 92.49 5.38 0.00 0.00 0.00 0.00 LRG011 08CB 76.77 22.63 76.77 22.63 0.00 0.00 0.00 0.00 LRG012 08CC 88.46 13.53 88.46 13.53 0.00 0.00 0.00 0.00 LRG013 08CD 87.28 12.03 87.28 12.03 0.00 0.00 0.00 0.00 LRG014 08DF 92.98 3.54 92.98 3.54 0.00 0.00 0.00 0.00 LRG015 08DE 82.71 11.74 82.71 11.74 0.00 0.00 0.00 0.00 SYS069 08FE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 TMP072 08DD 94.59 1.10 94.59 1.10 0.00 0.00 0.00 0.00 TSU020 08CE 84.19 30.27 84.19 30.27 0.00 0.00 0.00 0.00 TSU021 08CF 88.98 4.00 88.98 4.00 0.00 0.00 0.00 0.00 XADMP1 08EE 83.71 0.33 83.71 0.33 0.00 0.00 0.00 0.00 XAP002 08E0 64.41 0.21 64.41 0.21 0.00 0.00 0.00 0.00 XAP003 08E1 29.23 0.30 29.23 0.30 0.00 0.00 0.00 0.00 ------------------------------------------------------------------------------------------------------------------------------------
Figure 3-16. Detail VMX 3990-3 Cache Usage Report
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