ASM Page/Swap Activity Report
The ASM Page/Swap Activity Report tracks utilization and response of each page data set found in the RMF SCPPSD Files over the selected time range. A sample report is shown in Figure 2-68.
micsrm140
The ASM Page/Swap Activity Report tracks utilization and response of each page data set found in the RMF SCPPSD Files over the selected time range. A sample report is shown in Figure 2-68.
Report Options
The ASM Page/Swap Activity Report supports time, date, zone, and SYSID selection. The report options determine the level of the
MICS
database from which the data is selected, and the "by" value that is used for summarization.Data Elements
The elements reported are divided into three categories:
- Data Set Size
- Data Set Workload
- Data Set Service
Data Set Size
The data set size elements describe the allocation of the data set or data sets being described. When reporting by device type or page data set type, the elements in this section represent a total allocation over the data sets in a group (that is, over all local page data sets).
AVG SLOTS ALLOCATED
The average number of slots (or swap sets) allocated to the data set during the reporting period. When reporting by device type or page data set type, this value presents an average profile for all the data sets in this group.
AVG SLOTS USED
The average number of page data set slots (or swap data set swap sets) in use during this reporting interval. This value comes from the PSDAVU element in the SCPPSD File. RMF calculates this by sampling the Page Activity Reference or Swap Activity Reference Table each RMF cycle. When reporting by device type or page data type, this value presents an average profile for all the data sets in this group.
MAX SLOTS USED
The maximum number of page slots (or swap sets) found to be in use on this data set during any RMF sample. Note that the true maximum value can occur in between RMF cycles, but it cannot be smaller than this value. When reporting by device type or page data set type, this value is the maximum value found in any of the data sets included in this total. Investigations in sizing ASM data sets should always be done using this report summarized by data set name.
UNUSABLE SLOTS
The number of unusable slots (or swap sets) in this data set over the last RMF recording interval of the reporting period.
PERCENT SLOTS USED
The percentage of slots used over the reporting period. This value is equal to AVG SLOTS USED divided by AVG SLOTS ALLOCATED, multiplied by 100.
Data Set Workload
The data set workload elements describe the work done by a page/swap data set or by the group of data sets represented by this report. You can use these elements to identify situations where more devices are needed, as well as situations where the device selection algorithm may be causing a problem. Values in this section represent an individual data set or a group of data sets, depending on the reporting option selected.
TOTAL PAGING I/O
The number of paging I/O requests directed to this page or swap data set or group of page or swap data sets. Obtained from field IORSION of the I/O request blocks (IORBs) for this page/swap data set. Recorded for MVS/SE and later systems only. For MVS/SP 1.3, this value includes Resume I/Os (RIOs).
TOTAL DEVICE I/O
The total number of all I/O requests (both paging and non-paging) directed towards this device or group of devices. Obtained from adding together the I/O counts in the HARDVA File for this device or group devices
I/O CONTENTION INDEX
The ratio of the previous two values (paging I/O versus device I/O) for this device or group of devices. A high value could indicate a possible problem caused by having non-paging and paging data sets sharing the same device.
AVG I/O RATE
The average Start I/O rate per second for this data set or group of data sets during the RMF reporting interval. This value is only applicable to SE level MVS and above. For MVS/SP 1.3, this value includes Resume I/Os (RIOs). This value is calculated by
MICS
as:
PSDPSIOR=PSDSIO/DURATION
MAX I/O RATE
The highest rate of I/O request activity to this data set or group of data sets found for any RMF recording interval included in the reporting time interval. Recorded for MVS/SE and later systems only.
AVG PAGE RATE
The number of pages transferred per second. This element is applicable to "page" data sets only.
AVG PAGE BURST SIZE
The number of pages transferred per I/O. This element is applicable to "page" data sets only.
AVG DATASET UTIL
The percentage of time that the ASM (Auxiliary Storage Manager) considered this data set to be in use. RMF considers the data set to be in use if any IORB (I/O Request Block) associated with the data set is marked as being in use (data sets on multiple-exposure devices have multiple IORBs). For the device type or page data set type options, this is the average utilization of all data sets in the group. This value is calculated by
MICS
as:
PSDPCUSE=(100 * PSDUSE) / SAMPLES
MAX DATASET UTIL
The highest percentage "busy" encountered for this data set or group of data sets during any RMF recording interval included in the reported time interval. NOTE: This gives ASM's view of the data set. IOS's view may be different. Check the HARDVA Files for device busy. An indication of this difference will be given by the difference in the device service time and the device response time, which is defined below.
Data Set Service
The data set service elements give a measure of the average time to handle I/O requests to the page/swap data sets. The device activity file is used to factor in the device delays to compute the response time element. The difference between these two elements gives an indication of shared volume problems.
Note:
If you request reports by hour and are using the WEEKS timespan, the HARDVA File will be tested to make sure the file is in sequence by hour. If the file is not in sequence by hour, a warning message will be issued and several elements will be changed on the report to missing values.AVG RESPONSE TIME/IO
The number of seconds to handle a page or swap request, including IOS queuing delays. This field is calculated by including the I/O queue delay from the appropriate device activity files.
VG SERVICE TIME/IO
The number of seconds required to complete an average I/O to this page (or swap) data set. Maintained for MVS/SE or later versions only.
Note:
Any contention that may cause IOS to queue ASM's request is not visible to ASM.AVG SERVICE TIME/PAGE
The number of seconds required to transfer a page. This element is applicable only to true "page" data sets (that is, not swap).
Note:
Any contention that may cause IOS to queue ASM's request is not visible to ASM.MAX SERVICE TIME:
The highest (worst) average service time for I/O requests found in any RMF recording interval in the time covered by this record.
ASM Page/Swap Activity Report Sample
Figure 2-68. Sample Hourly ASM Page/Swap Activity Report
CA MICS Performance Manager HOURLY ASM DATASET ACTIVITY REPORT FOR ZONE = 1 SYSTEM = XA01 RUNDATE = SEP 19, yyyy DSN = SYS1.PAGE109 UNIT = 272 DEVICE TYPE = 3380 PAGE SPACE TYPE = LOCAL -------------------------------------------------------------------------------------------------------------------------------- | | | HOUR/DATE (HR-MM/DD): 00-09/yy 01-09/yy 02-09/yy 03-09/yy 04-09/yy 06-09/yy yy-09/yy 08-09/yy 09-09/yy 10-09/yy CHANGE % | | | |------------------------------------------------------------------------------------------------------------------------------| | | | DATASET SIZE | | ------------ | | | | AVG SLOTS ALLOCATED 45000 45000 45000 45000 45000 45000 45000 45000 45000 45000 --- | | AVG SLOTS USED 4322.00 4213.00 3927.25 2935.00 2834.06 158.00 1186.00 2017.44 2166.50 2945.13 -31.85 % | | MAX SLOTS USED 4657.00 4266.00 4197.00 3609.00 3009.00 334.00 1722.00 2240.00 2401.00 3373.00 -27.57 % | | UNUSABLE SLOTS 0 0 0 0 0 0 0 0 0 0 N/A | | PERCENT SLOTS USED 9.60 % 9.36 % 8.72 % 6.52 % 6.29 % 0.35 % 2.63 % 4.48 % 4.81 % 6.54 % -31.87 % | | | |------------------------------------------------------------------------------------------------------------------------------| | | | DATASET WORKLOAD | | ---------------- | | | | TOTAL PAGING I/O 21 358 331 276 252 29 443 1588 847 2445 1542.85 % | | TOTAL DEVICE I/O 23 408 345 356 254 29 446 1602 849 2447 539.13 % | | I/O CONTENTION INDEX 0.095 0.014 0.004 0.290 0.008 0.000 0.007 0.009 0.002 0.001 -98.94 % | | AVG SIO RATE 0.37 0.10 0.09 0.08 0.08 0.05 0.12 0.44 0.24 0.54 45.94 % | | MAX SIO RATE 0.66 0.15 0.15 0.26 0.11 0.05 0.16 0.77 0.28 0.68 3.03 % | | AVG PAGE RATE 0.81 0.17 0.25 0.12 0.16 0.61 0.62 1.20 0.77 1.43 76.54 % | | AVG PAGE BURST SIZE 2.21 1.68 2.70 1.53 2.12 12.79 5.02 2.72 3.29 2.64 19.45 % | | AVG DATASET UTIL 0.80 % 0.13 % 0.27 % 0.02 % 0.06 % 0.32 % 0.22 % 0.55 % 0.58 % 1.00 % 23.45 % | | MAX DATASET UTIL 1.44 % 0.33 % 0.55 % 0.11 % 0.22 % 0.32 % 0.44 % 1.10 % 0.66 % 1.44 % --- | | | |------------------------------------------------------------------------------------------------------------------------------| | | | DATASET SERVICE | | --------------- | | | | AVG RESPONSE TIME/IO 0.022 0.014 0.030 0.004 0.008 0.069 0.018 0.013 0.025 0.018 -18.18 % | | AVG SERVICE TIME/IO 0.022 0.014 0.030 0.004 0.008 0.069 0.018 0.013 0.025 0.018 -18.18 % | | AVG SERVICE TIME/PAGE 0.010 0.008 0.011 0.002 0.004 0.005 0.004 0.005 0.008 0.007 -30.00 % | | MAX SERVICE TIME 0.011 0.014 0.015 0.003 0.016 0.005 0.005 0.006 0.009 0.009 -18.18 % | | | --------------------------------------------------------------------------------------------------------------------------------