HP OpenVMS Systems Documentation

HP OpenVMS DCL Dictionary

Resets systemwide I/O caching statistics for the extended file cache (XFC).

OPER privilege is required to execute this command.

Format

SET CACHE/RESET

Parameters

None.

Description

The SET CACHE/RESET command resets several of the systemwide I/O caching statistics that are displayed by the SHOW MEMORY/CACHE and SDA SHOW MEMORY commands. Statistics that are reset include: I/O counts, hit rates, hit counts, reads bypassing cache, and the read/write ratio.

A timestamp displays the time the cache was last reset, thus subsequent SHOW MEMORY/CACHE commands display statistics from this time.

Example

$ SHOW MEMORY/CACHE
              System Memory Resources on 22-AUG-2001 11:22:22.50

Extended File Cache  (Time of last reset: 16-AUG-2001 11:16:24.96)
 Allocated (Mbytes)     151.39   Maximum size (Mbytes)    1024.00
 Free (Mbytes)            0.21   Minimum size (Mbytes)       0.23
 In use (Mbytes)        151.18   Write hit rate                 0%
 Read hit rate              97%  Write I/O count             5321
 Read I/O count         208052   Write hit count                0
 Read hit count         203761   Writes bypassing cache         0
 Reads bypassing cache    1787   Vols in Full XFC mode          0
 Files cached open         316   Vols in VIOC Compatible mode   1
 Files cached closed       300   Vols in No Caching mode        0
 Read/Write ratio           97%  Vols in Perm. No Caching mode  0
      

This example shows the cache statistics prior to issuing the SET CACHE/RESET command.

$ SET CACHE/RESET

This command resets the cache statistics and updates the timestamp.

$ SHOW MEMORY/CACHE System Memory Resources on 22-AUG-2001 11:27:41.11 Extended File Cache (Time of last reset: 22-AUG-2001 11:27:37.76) Allocated (Mbytes) 151.39 Maximum size (Mbytes) 1024.00 Free (Mbytes) 0.21 Minimum size (Mbytes) 0.23 In use (Mbytes) 151.18 Write hit rate 0% Read hit rate 100% Write I/O count 0 Read I/O count 9 Write hit count 0 Read hit count 9 Writes bypassing cache 0 Reads bypassing cache 0 Vols in Full XFC mode 0 Files cached open 316 Vols in VIOC Compatible mode 1 Files cached closed 300 Vols in No Caching mode 0 Read/Write ratio 100% Vols in Perm. No Caching mode 0

This example shows the reset cache statistics and the modified timestamp.