|
|
|
Figure 2-90 shows the Shared DASD Analysis Report resulting
from the information entered on the IOA Shared DASD Analysis
Report inquiry panel. There are a number of values in the
report that you should carefully examine.
o The total percent utilization for all systems in the
configuration, that is, the left-most column labeled %
UTIL. If this value is in excess of 30-35 percent, then
significant problems can be expected both in internal
queuing and average response time. The average response
time will increase significantly, due to significant
internal queuing for the device.
o High average internal queue time (the center column
labeled QUEUE). This is the symptom of multiple address
spaces in a single system competing for a single device.
You should examine the contents of the volume to see if
the volume could be split into two separate volumes on
different paths.
o Utilization of a shared device by a single system. This
is shown most graphically by the %SIO column. If a
device is consistently utilized by only a single system,
you should raise the question as to why the volume is
physically shareable (or at least online) to the other
system. This problem can be corrected by normally
varying it offline or by making it physically
non-shareable.
o High values (that is, greater than 1.1) of the R/R and
R/S columns. These values indicate systems whose
performance is being significantly impacted by the other
systems that share the device.
By reviewing these values, you can identify devices where the
effects of shared DASD are having a significant impact.
Generally, you should ask the question, "why should this
device be shared?" rather than, "why not share the device?"
CA MICS Performance Manager SHARED DASD ANALYSIS REPORT INTERVAL START: 27DECyy:15:44 INTERVAL END : 04JAN91:15:59 DURATION : 16:00 DEV DEVICE TOTAL % ---AVERAGE TIME (MS)--- DEV SIO % % AV RESP AV SERV AV QUE ADR VOLSER TYPE SIO UTIL RESP. SERVICE QUEUE SYSID ADR COUNT SIO UTIL TIME MS R/R TIME MS R/S TIME MS R/Q ---- ------ -------- ----- ----- ------- ------- ------- ----- ---- ----- --- ----- ------- --- ------- --- ------- --- 16C PAG16C 3380 111E3 12.5 33.3 32.5 0.8 SYSA 16C 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 16C 111E3 100 12.5 33.3 1.0 32.5 1.0 0.8 1.0 SYSC 16C 22 0 0.0 45.5 1.4 45.5 1.4 0.0 0.0 16D SMF302 3380 95251 7.2 21.2 21.0 0.2 SYSA 16D 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 16D 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSC 16D 95251 100 7.2 21.2 1.0 21.0 1.0 0.2 1.0 161 PAG161 3380 83489 6.4 23.4 22.0 1.4 SYSA 161 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 161 83467 100 6.4 23.4 1.0 22.0 1.0 1.4 1.0 SYSC 161 22 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 168 PAG168 3380 108E3 12.6 34.3 33.4 0.9 SYSA 168 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 168 108E3 100 12.6 34.3 1.0 33.4 1.0 0.9 1.0 SYSC 168 22 0 0.0 45.5 1.3 0.0 0.0 45.5 49 169 SMF301 3380 37098 2.8 21.6 21.1 0.6 SYSA 169 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 169 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSC 169 37098 100 2.8 21.6 1.0 21.1 1.0 0.6 1.0 17D PAG17D 3380 47671 7.0 57.0 42.6 14.5 SYSA 17D 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 17D 47649 100 7.0 57.1 1.0 42.6 1.0 14.5 1.0 SYSC 17D 22 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 17F M33803 3380 82955 4.4 25.5 21.3 4.3 SYSA 17F 44738 54 1.8 29.6 1.2 23.0 1.1 6.7 1.6 SYSB 17F 20426 25 1.3 21.1 0.8 18.7 0.9 2.4 0.6 SYSC 17F 17791 21 1.3 20.2 0.8 19.9 0.9 0.3 0.1 171 PAG171 3380 47988 6.6 52.0 39.5 12.6 SYSA 171 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 171 47966 100 6.6 52.1 1.0 39.5 1.0 12.6 1.0 SYSC 171 22 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 173 PAG173 3380 47793 6.4 50.2 38.3 11.9 SYSA 173 0 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SYSB 173 47771 100 6.4 50.3 1.0 38.3 1.0 11.9 1.0 SYSC 173 22 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 174 M33801 3380 38972 2.0 21.0 19.9 1.1 SYSA 174 20741 53 0.7 20.4 1.0 19.0 1.0 1.4 1.3 SYSB 174 7622 20 0.5 18.8 0.9 18.1 0.9 0.7 0.6 SYSC 174 10609 27 0.9 23.8 1.1 23.0 1.2 0.8 0.8
Figure 2-90. Case Study - Shared DASD Analysis Report
| Copyright © 2012 CA. All rights reserved. | Tell Technical Publications how we can improve this information |