SCF Reference Manual for the Storage Subsystem (G06.28+, H06.05+, J06.03+)

Configuring Disk Cache
1. Review information about the CACHE attribute.
2. List current disk cache configuration information:
1-> INFO $DATA00, CACHE
STORAGE - Cache Info Magnetic DISK \NBSTS01.$DATA00 (Cn = config, Al = alloc)
Size______512_________1K_________2K_________4K________32K
Cn -1 -1 -1 -1 -1
Al 512 512 512 4096 512
Bytes Allocated To Cache: 34560 KB
3. Save accumulated statistical data before flushing it:
1-> STATS / OUT STATSLOG / $DATA00
SCF W20052 Creating file \NBSTS01.$DATA00.STATSLOG.STATSLOG
==SCF - T9082H01 - (23JUN11) (02MAY11) - 07/23/2013 14:39:17 System \NBSTS01
==(C) 1986 Tandem (C) 2006 Hewlett Packard Development Company, L.P.
STORAGE - Stats DISK \NBSTS01.$DATA00
Cache Statistics:
Current Time............. 23 Jul 2013, 14:39:17.511
Counters Reset Time...... 23 Jul 2013, 14:26:34.317
Elapsed Time............. 0 days, 00:12:43
Bytes Allocated To Cache. 34560 KB
Writes/Control Point..... 0.00
Block Size___________512_________1K_________2K_________4K
Requested.... -1 -1 -1 -1
Allocated.... 512 512 512 4096
Blocks In Use 0 0 0 208
Blocks Dirty. 0 % 0 % 0 % 0 %
Cache Reads.. 1 % 0 % 0 % 82 %
Read Hits.... 90 % 0 % 100 % 99 %
Read Misses.. 10 % 0 % 0 % 1 %
Cache Writes. 99 % 100 % 100 % 18 %
Write Dirties 0 % 0 % 0 % 0 %
Write Cleans. 98 % 98 % 98 % 97 %
Write Misses. 2 % 2 % 2 % 3 %
Cache Calls.. 1001 198 596 1847
Cache Faults. 0 0 0 0
Audit Forces. 0 0 0 0
4. For an explanation of the display fields and for help determining if memory allocation is
adequate, see “Displaying Disk Cache Configuration Information” (page 59).
5. Change the 4K cache block size to increase the number of blocks allocated to 2000:
-> ALTER $DATA10, CACHE ( 4K, 2000 )
6. View the new cache configuration information:
1-> INFO $DATA00, CACHE
STORAGE - Cache Info Magnetic DISK \NBSTS01.$DATA00 (Cn = config, Al = alloc)
Size___________512___________1K___________2K_________4K__________32K
Cn -1 -1 -1 -1 -1
Al 512 512 512 4096 512
Bytes Allocated To Cache: 34560 KB
Altering Disk Attribute Values 87