HP StorageWorks XP Disk Array Mainframe Host Attachment and Operations Guide (A5951-96154, September 2010)

Return CodeStorage SystemArgumentCommand
CC = 0, Readcheck parameter not allowed.RAMACCPVOLUME
CC=0XP disk array
z/OS (MVS) Cache operations
To display the cache statistics under MVS DFSMS, use the operator command: D SMS, CACHE. The
following example shows the cache statistics reported by the storage system. The storage system
reports cache statistics for each SSID in the storage system. Because the dynamic cache management
algorithm has been enhanced, the read and write percentages for the storage system are displayed
as N/A. For further information on MVS DFSMS cache reporting, see the IBM documentation.
SSID DEVS READ WRITE HIT RATIO FW BYPASSES
0004 15 N/A N/A 50% 0
0005 11 N/A N/A 0% 0
0006 11 N/A N/A 87% 0
0007 10 N/A N/A 87% 0
****************************************************
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
The storage system supports the following MVS cache operations:
• IDCAMS LISTDATA COUNTS. When the <system> parameter is used with the LISTDATA command,
the user must issue the command once for each SSID to view the entire storage system image. The
following shows a JCL example of the LISTDATA COUNTS command.
//LIST JOB. . . . . .
//COUNT1 EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN DD *
LISTDATA COUNTS VOLUME(VOL000) UNIT(3390) SUBSYSTEM
LISTDATA COUNTS VOLUME(VOL064) UNIT(3390) SUBSYSTEM
LISTDATA COUNTS VOLUME(VOL128) UNIT(3390) SUBSYSTEM
LISTDATA COUNTS VOLUME(VOL192) UNIT(3390) SUBSYSTEM
/*
• Subsystem counter reports. The cache statistics reflect the logical caching status of the volumes.
For the storage system, HP recommends that you set the nonvolatile storage (NVS) ON and the
DASD fast write (DFW) ON for all logical volumes. This will not affect the way the storage system
caches data for the logical volumes.
The default caching status for the storage system is:
• CACHE ON for the storage system
• CACHE ON for all logical volumes
• CACHE FAST WRITE ON for the storage system
• NVS OFF for the storage system (Change NVS to ON for the XP disk array.)
• DFW OFF for all volumes (Change DFW to ON for the XP disk array.)
XP Disk Array Mainframe Host Attachment and Operations Guide 45