HP StorageWorks XP Disk Array Mainframe Host Attachment and Operations Guide XP24000, XP20000 (A5951 - 96151, September 2007)

//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.)
NOTE:
In normal cache replacement, bypass cache, or inhibit cache loading mode, the storage system performs
a special function to determine whether the data access pattern from the host is sequential. If the access
pattern is sequential, the storage system transfers contiguous tracks from the disks to cache ahead of time
to improve cache hit rate. Due to this advanced track transfer, the storage system shows the number of
tracks transferred from the disks to the cache slot at DASD/CACHE of the SEQUENTIAL in TRANSFER
OPERATIONS field in the storage system counters report, even though the access mode is not sequential.
IDCAMS LISTDATA STATUS. The LISTDATA STATUS command generates status information for a specific
device within the storage system. The XP disk array reports two storage sizes:
• Subsystem storage. This field shows capacity in bytes of cache. For a storage system with more
than one SSID, the cache is shared among the SSIDs instead of being logically divided. This
strategy ensures backup battery power for all cache in the storage system. For the storage system,
this field shows three-fourths (75%) of the total cache size.
• Nonvolatile storage. This field shows capacity in bytes of random access cache with a backup
battery power source. For the storage system, this field shows one-fourth (25%) of the total cache
size.
IDCAMS SETCACHE. The storage system supports the IDCAMS SETCACHE commands, which manage
caching for subsystem storage through the use of one command (except for REINITIALIZE). The following
SETCACHE commands work for the subsystem storage across multiple SSIDs:
• SETCACHE SUBSYSTEM ON|OFF
• SETCACHE CACHEFASTWRITE ON|OFF
• SETCACHE NVS ON|OFF
• SETCACHE DESTAGE
NOTE:
The SETCACHE REINITIALIZE command reinitializes only the logical storage system specified by the SSID.
You must issue the REINITIALIZE command once for each defined SSID.
z/OS Operations56