Monitor MONDCSS SegmentLast updated 27 June 2005 Computing the Size of the Monitor DCSSThe monitor DCSS is broken into two sections with 2 subsections in each. These are Sample (config, standard) and Event (config, standard).
AREA Default Size in Pages Change Size with this command
Sample Data 50% of seg - 241 MONITOR START PARTITION n
Sample Config 241 MONITOR SAMPLE CONFIG SIZE n
Event Data 50% of seg - 68 MONITOR START PARTITION n
Event Config 68 MONITOR EVENT CONFIG SIZE n
* note the MONITOR START PARTITION command sets size of EVENT partition
with the left over being the Sample size.
So a monitor DCSS created by following commands -
CP DEFSEG MONDCSS 2200-26FF SC RSTD
CP SAVESEG MONDCSS
would have a layout like the following:
39.0M+---------------------+
| | S
| | A
| Data = rest | M
| 399 pages | P 640 pages
|.................... | L
| Config = 241 pages | E
36.5M+---------------------+ ---
| (572 pages) | E
| Data = rest | V
| | E 640 pages
|.....................| N
| Config = 68 pages | T
34.0M+---------------------+
Use the Performance Manual section "Calculating the Space Needed for the Saved Segment" (Chapter 9) to compute size needed for the 4 areas. Assume the values you get are:
Sample Data 1886 pages
Sample Config 350 pages
Event Data 256 pages
Event Config 68 pages
You would need a 10 meg segment:
CP DEFSEG MONDCSS 2200-2BFF SC RSTD
CP SAVESEG MONDCSS
Set Config sizes:
CP MONITOR SAMPLE CONFIG SIZE 350
CP MONITOR EVENT CONFIG SIZE 68
Start and set partition size:
CP MONITOR START PARTITION 324
The layout would be:
44.0M+---------------------+
| |
| |
| | S
| | A
| Data = 1886 pages | M
| | P 2236 pages
|.................... | L
| Config = 350 pages | E
| |
35.3M+---------------------+ ---
| Data = 256 pages | E
| | V 324 pages
|.....................| E
| Config = 68 pages | N
34.0M+---------------------+ T
To determine size of existing monitor DCSS, you will need to issue a few commands - QUERY NSS and QUERY MONITOR. QUERY NSS NAME MONDCSS MAP results in - FILE FILENAME FILETYPE MINSIZE BEGPAG ENDPAG TYPE CL #USERS PARMREGS VMGROUP 0475 MONDCSS CPDCSS N/A 02200 02BFF SC R 00006 N/A N/Awhich tells us that the total size is 10 megabytes (2BFF minus 2200 plus 1 page). Then the output from QUERY MONITOR might look like this -
MONITOR EVENT ACTIVE BLOCK 4 PARTITION 324
MONITOR DCSS NAME - MONDCSS
CONFIGURATION SIZE 68 LIMIT 1 MINUTES
CONFIGURATION AREA IS FREE
USERS CONNECTED TO *MONITOR - PERFSVM
MONITOR DOMAIN ENABLED
PROCESSOR DOMAIN DISABLED
STORAGE DOMAIN DISABLED
SCHEDULER DOMAIN DISABLED
SEEKS DOMAIN DISABLED
USER DOMAIN DISABLED
I/O DOMAIN DISABLED
APPLDATA DOMAIN DISABLED
MONITOR SAMPLE ACTIVE
INTERVAL 1 MINUTES
RATE 2.00 SECONDS
MONITOR DCSS NAME - MONDCSS
CONFIGURATION SIZE 350 LIMIT 1 MINUTES
CONFIGURATION AREA IS FREE
USERS CONNECTED TO *MONITOR - PERFSVM
MONITOR DOMAIN ENABLED
SYSTEM DOMAIN ENABLED
PROCESSOR DOMAIN ENABLED
STORAGE DOMAIN ENABLED
USER DOMAIN ENABLED
ALL USERS ENABLED
I/O DOMAIN ENABLED
ALL DEVICES ENABLED
APPLDATA DOMAIN ENABLED
ALL USERS ENABLED
From this you can see that of the 2560 pages (10MB), 324 belong to
Event. This leaves 2236 for Sample. Of the 324 for Event, 68 are for
configuration. Of the 2236 for Sample, 350 are for configuration.
NOTE: If the size of the Sample Configuration Record area is too small, missing or incomplete monitor records can occur. This usually happens when there are a large number of devices available on your system. To increase the size of the Sample Configuration Record area use the MONITOR SAMPLE CONFIG command with the SIZE option. If you are using IBM Performance Toolkit for z/VM (PERFKIT module) the missing and/or incomplete monitor records are detected when you start Performance Toolkit for z/VM and the message FCXPMN446E Incomplete monitor data: SAMPLE CONFIG size too small will be issued.
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