Mvs Cache Operations; Figure 4.22 Displaying Cache Statistics Using Mvs Dfsms; Figure 4.23 Idcams Listdata Counts (Jcl Example) - Hitachi 9900 User And Reference Manual

4.3.3

MVS Cache Operations

To display the 9900 cache statistics under MVS DFSMS, use the following operator command:
D SMS, CACHE. Figure 4.22 shows the cache statistics reported by the 9900. The 9900
reports cache statistics for each SSID in the subsystem. Because the dynamic cache
management algorithm has been enhanced, the read and write percentages for the 9900 are
displayed as N/A. For further information on MVS DFSMS cache reporting, please refer to the
®
IBM document DFSMSdfp Storage Administrator Reference (SC28-4920).
SSID
0004
0005
0006
0007
****************************************************
SSID=SUBSYSTEM IDENTIFIER
DEVS=NUMBER OF MANAGED DEVICES ATTACHED TO SUBSYSTEM
READ=PERCENT OF DATA ON MANAGED DEVICES ELIGIBLE FOR CACHING
WRITE=PERCENT OF DATA ON MANAGED DEVICES ELIGIBLE FOR FAST WRITE
HIT RATIO=PERCENT OF READS WITH CACHE HITS
FW BYPASSES=NUMBER OF FAST WRITE BYPASSES DUE TO NVS OVERLOAD

Figure 4.22 Displaying Cache Statistics Using MVS DFSMS

The 9900 supports the following MVS cache operations:
IDCAMS LISTDATA COUNTS. When the <subsystem> parameter is used with the
LISTDATA command, the user must issue the command once for each SSID to view the
entire 9900 image. Figure 4.23 shows a JCL example of the LISTDATA COUNTS command.
//LIST JOB. . . . . .
//COUNT1 EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN DD *
LISTDATA
LISTDATA
LISTDATA
LISTDATA
/*

Figure 4.23 IDCAMS LISTDATA COUNTS (JCL example)

DEVS READ WRITE
15 N/A N/A
11 N/A N/A
11 N/A N/A
10 N/A N/A
COUNTS VOLUME(VOL000) UNIT(3390)
COUNTS VOLUME(VOL064) UNIT(3390)
COUNTS VOLUME(VOL128) UNIT(3390)
COUNTS VOLUME(VOL192) UNIT(3390)
HIT RATIO
50% 0
0% 0
87% 0
87% 0
SUBSYSTEM
SUBSYSTEM
SUBSYSTEM
SUBSYSTEM
Hitachi Lightning 9900™ User and Reference Guide
FW BYPASSES
73