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I/O Performance and Monitoring Tools 129
• Disconnect time, which covers all internal LCU delays primarily due to a
prerequisite process in the storage server; for instance, staging activity for
cache misses, or PPRC propagation of the I/O to the secondary site
•
Connect time, which covers effective data transfer activity
Queuing time is called
I/O supervisor queuing (IOSQ) time in RMF reports, and
covers delays involved by aggregate application interactions on the same volume
for that LPAR.
Several LPARs (weighted by activity) sharing the same storage servers must be
consolidated to establish value correlations with CACHE reporting.
Figure 50. Direct Access Device Activity Report
The Direct Access Device Activity report provides detailed information for each
(functional) volume and consolidates the information at the LCU (or Storage
Group when required) level.
The fields to review are:
• LCU, reference number used lo locate which CHAN report data to analyze
• DEVICE ACTIVITY RATE, rate per second at which start subchannel (SSCH)
instructions to the device completed successfully
• AVG RESP TIME, response time in milliseconds
• AVG IOSQ TIME, queuing time in IOSQ on the device
• AVG PEND TIME, pending time
• AVG DISC TIME, disconnect time
DIRECT ACCESS DEVICE ACTIVITY
OS/390 SYSTEM ID IPO4 START 11/19/1998-10.30.00 INTERVAL 001.00.00
REL. 02.05.00 RPT VERSION 2.4.0 END 11/19/1998-11.30.00 CYCLE 1.000 SECONDS
TOTAL SAMPLES = 3,600 IODF = 40 CR-DATE: 11/05/98 CR-TIME: 16.56.05 ACT: POR
DEVICE AVG AVG AVG AVG AVG AVG AVG AVG % % %AVG% %
STORAGE DEV DEVICE VOLUME LCU ACTIVITY RESP IOSQ DPB CUB DB PEND DISC CONN DEV DEV DEV NUMBER ANY MT
GROUP NUM TYPE SERIAL RATE TIME TIME DLY DLY DLY TIME TIME TIME CONN UTIL RESV ALLOC ALLOC PEND
SGDB2TS 0103 33903 VLD273 0026 0.053 20 0 0.0 0.0 0.0 0.6 13.0 6.7 0.04 0.10 0.0 64.9 100.0 0.0
SGDB2TS 0105 33903 VLD274 0026 0.102 4 0 0.0 0.0 0.0 0.6 1.8 1.5 0.02 0.03 0.0 22.0 100.0 0.0
SGDB2TS 0107 33903 VLD275 0026 0.706 15 0 0.0 0.0 0.0 0.5 12.3 2.0 0.14 1.01 0.0 31.0 100.0 0.0
SGDB2TS 0109 33903 VLD276 0026 0.224 12 0 0.0 0.0 0.0 0.5 9.8 1.4 0.03 0.25 0.0 22.0 100.0 0.0
SGDB2TS 013A 33903 VLD270 0026 0.003 5 0 0.0 0.0 0.0 0.3 3.6 0.7 0.00 0.00 0.0 0.0 100.0 0.0
SGDB2TS 013B 33903 VLD301 0026 0.109 8 0 0.0 0.0 0.0 0.6 6.2 1.4 0.02 0.08 0.0 62.0 100.0 0.0
SGDB2TS 0384 33903 VLD312 0031 0.008 9 0 0.0 0.0 0.0 0.7 5.1 3.6 0.00 0.01 0.0 17.0 100.0 0.0
SGDB2TS 0396 33903 VLD286 0031 0.036 7 0 0.0 0.0 0.0 0.9 5.1 1.3 0.00 0.02 0.0 60.0 100.0 0.0
SGDB2TS 03BF 33903 VLD219 0031 0.065 21 9 0.0 0.0 0.1 0.9 6.4 4.9 0.03 0.07 0.0 29.0 100.0 0.0
SGDB2TS 0D0B 33903 VLD265 0063 0.131 2 0 0.0 0.0 0.0 0.4 0.6 1.5 0.02 0.03 0.0 14.0 100.0 0.0
SGDB2TS 0D13 33903 VLD285 0063 0.018 4 0 0.0 0.0 0.0 0.4 2.9 1.0 0.00 0.01 0.0 20.7 100.0 0.0
SGDB2TS 0D14 33903 VLD307 0063 0.062 2 0 0.0 0.0 0.0 0.4 0.5 1.0 0.01 0.01 0.0 20.9 100.0 0.0
SGDB2TS 0D22 33903 VLD310 0063 0.011 6 0 0.0 0.0 0.0 0.5 4.4 1.1 0.00 0.01 0.0 32.0 100.0 0.0
SGDB2TS 4066 33903 VLD538 0076 0.675 20 4 0.0 0.0 0.0 0.5 11.4 4.1 0.28 1.05 0.0 103 100.0 0.0
SGDB2TS 4067 33903 VLD539 0076 3.926 31 15 0.0 0.0 0.0 0.3 8.9 6.5 2.54 6.05 0.0 107 100.0 0.0
SGDB2TS 4068 33903 VLD540 0076 2.526 20 5 0.0 0.0 0.0 0.3 5.4 9.5 2.40 3.75 0.0 120 100.0 0.0
SGDB2TS 407F 33903 VLD563 0076 1.076 12 2 0.0 0.0 0.0 0.4 7.2 2.5 0.27 1.05 0.0 112 100.0 0.0
SGDB2TS 4080 3390 VLD564 0077 1.276 13 3 0.0 0.0 0.0 0.4 7.1 2.4 0.31 1.21 0.0 87.7 100.0 0.0
SGDB2TS 4081 3390 VLD565 0077 1.456 16 2 0.0 0.0 0.0 0.4 7.1 5.8 0.84 1.87 0.0 90.9 100.0 0.0
SGDB2TS 4095 3390 VLD585 0077 0.179 15 0 0.0 0.0 0.0 0.9 10.4 3.9 0.07 0.26 0.0 54.0 100.0 0.0
SGDB2TS 4096 3390 VLD586 0077 1.797 12 1 0.0 0.0 0.0 0.3 6.9 3.8 0.68 1.93 0.0 119 100.0 0.0
SGDB2TS SG 107.550 17 5 0.0 0.0 0.0 0.4 7.4 3.9 0.43 1.27 0.0 6879 100.0 0.0