FCX178, Minidisk Cache Storage Log Screen – MDCSTOR

Performance Toolkit Subcommand: MDCSTOR.

The Minidisk Cache Storage Log Screen (FCX178) shows minidisk cache storage utilization data by time:

Figure 1. Layout of Minidisk Cache Storage Log Screen (FCX178)

 FCX178      CPU nnnn  SER nnnnn  Interval HH:MM:SS - HH:MM:SS    Perf. Monitor

           <---------------- Main Storage Frames -----------------> <----------
 Interval         <--Actual--->    Min    Max  Page    Steal
 End Time   Ideal   <2GB   >2GB    Set    Set Del/s Invokd/s   Bias  Ideal Actu
 >>Mean>>   94948  42088 519166      0 655360   299     .240   1.00  16384  162
 11:23:58  102479  41600 380397      0 655360   244     .200   1.00  16384  162
 11:24:58  102522  41655 387876      0 655360   245     .200   1.00  16384  163
 11:25:58  102216  41689 394707      0 655360   271     .250   1.00  16384  161
 11:26:58  101257  41730 402826      0 655360   279     .217   1.00  16384  163
 11:27:58  101179  41743 413336      0 655360   322     .250   1.00  16384  162
 11:28:58  103179  41761 423091      0 655360   222     .183   1.00  16384  161
 11:29:58  100248  41769 429965      0 655360   340     .250   1.00  16384  163
 11:30:58   99880  41790 438826      0 655360   273     .233   1.00  16384  162
 11:31:58   99335  41874 447344      0 655360   300     .233   1.00  16384  162
 11:32:58   98832  41938 456691      0 655360   257     .200   1.00  16384  161
 11:33:58   98168  41974 464636      0 655360   300     .233   1.00  16384  163
 11:34:58   98062  41992 473121      0 655360   251     .217   1.00  16384  163
 11:35:58   97119  41998 482695      0 655360   308     .250   1.00  16384  162
 11:36:58   96477  41986 491686      0 655360   307     .250   1.00  16384  161
 11:37:58   95730  41963 500476      0 655360   300     .233   1.00  16384  162
 See MDCACHE display for minidisk cache activity log
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The information shown is based on CP monitor SYSTEM domain SAMPLE data.

The leftmost column contains the end time:

(format hh:mm:ss)

of the monitor interval for which the values were calculated. Note that only part of the performance variables can be shown on the 80 columns of an ordinary screen: use the LEFT/RIGHT subcommands, or the corresponding PF-keys, for shifting the display window to the left or to the right for viewing the remaining data columns.

The first entry is reserved for the overall averages since the last RESET subcommand, or since data collection was activated. It is designated by the string >>Mean>> in the 'Interval End Time' column.

Field Description:

Interval End Time: The end time of the monitor interval or the BYTIME interval for which the values were calculated.
In the case of the >>Mean>> entry, you can find the relevant interval in the header line.

Main Storage Frames:

Ideal: The ideal number of main storage page frames in the minidisk cache (based on average age of a page in DPA, determined by arbiter)
Actual <2GB: The actual number of main storage page frames used for the minidisk cache below the 2GB line
Actual >2GB: The actual number of main storage page frames used for the minidisk cache above the 2GB line. The field is available only for z/VM systems running in 64-bit mode.
Min Set: The minimum number of main storage pages to be used for the minidisk cache
Max Set: The maximum number of main storage pages to be used for the minidisk cache
Page Del/s: The number of main storage pages deleted from cache per second
Steal Invokd/s: The number of times the steal function was invoked to steal main storage pages from cache per second
Bias: The bias for minidisk cache usage of real storage. A number less than 1 is a bias against minidisk cache; a number greater than 1 is a bias for minidisk cache.

Expanded Storage Blocks:

Ideal: The ideal number of expanded storage blocks in the minidisk cache (based on average age of an XSTORE block, as determined by arbiter)
Actual: The actual number of expanded storage blocks used for the minidisk cache
Min Set: The minimum number of expanded storage blocks to be used for the minidisk cache
Max Set: The maximum number of expanded storage blocks to be used for the minidisk cache
Page Del/s: The number of XSTORE pages deleted from cache per second
Steal Invokd/s: The number of times the steal function was invoked to steal expanded storage pages from cache per second
Bias: The bias for minidisk cache use of expanded storage. A number less than 1 is a bias against minidisk cache; a number greater than 1 is a bias for minidisk cache.
Age: The average age of paging XSTORE blocks

Effect of 'AVERAGE' and 'INTERIM' subcommands: None.