Evaluate Performance in Detail › Performance Evaluation Report › Interpret cluster-wide Hot File Statistics

Interpret cluster-wide Hot File Statistics

In the Performance Evaluation Report, the hot file statistics follow the cluster-wide tape statistics. The hot file statistics highlight the files with the most I/O operations for each disk in the configuration. By default, the 20 hottest files are provided for each disk; however, you can change this number by specifying /HOTFILE_LIMIT=n on the command line.

To display only the hot file statistics section of the report, use the following qualifier:

/INCLUDE=HOTFILE_STATISTICS

To disable the hot file statistics display from the Performance Evaluation Report, use the following qualifier:

/INCLUDE=NOHOTFILE_STATISTICS  

The following example shows the hot file statistics section of the Performance Evaluation report:

Performance                          CLUSTER                            Page   1
Evaluation                                                          PA Vx.x
					Wednesday 04-JAN-2006 11:00 to 11:45

  +-----------------------------------------------------------------------+
  | The following table gives a summary of the top  20 hottest files      |
  | as collected for disks with a queue higher than the /HOT_QUEUE value. |
  +-----------------------------------------------------------------------+

IO Rate  %   %     Peak
--------- Ops Ops   Time   Rec
Dev  Avg Peak Rds Spl DD-HH:MM Cnt     File spec
--- ---- ---- --- --- -------- --- ------------------------------------------
BORDEAUX  ($3$DUA29)
 1   2    3     4   5     6      7            8
    0.03 0.03   0  33  4-11:46   1 [VAXMAN.OSF] PROJECT_PLAN.TXT;5
    0.02 0.02   0  50  4-11:46   1  (40672,3,0)
    0.01 0.02 100   0  4-11:44   2 [VAXMAN.REMINDER] WRK.DIR;1
    0.01 0.01 100   0  4-11:46   1 [LANGELO] CIRRUS_ROM.DIR;1
       .    .   .   .        .   .       .
       .    .   .   .        .   .       .
       .    .   .   .        .   .       .
ZINFANDEL  ($3$DUA30)
    3.25 3.42  55   0  4-11:44   2  (Non Virtual QIO)
    0.03 0.03  40   0  4-11:46   2 [DECPS.DATABASE] PSDC$YQUEM_1991OCT04.CPD;1
    0.02 0.03 100  50  4-11:44   2 [DECPS.DATABASE] PSDC$SCHEDULE.DAT;1
    0.02 0.02 100   0  4-11:44   1 [DECPS] DATABASE.DIR;1

The following statements are keyed to the columns in the previous example:

1. The disk device and volume name.
2. The average I/O rate, in I/O operations per second, for the intervals of time when the file is “hot.”
3. The peak I/O rate, in I/O operations per second, for the interval record when the file is “hottest.”
4. The percentage of I/O activity devoted to file READs.
5. The percentage of I/O activity where a split I/O operation occurred.
6. The interval time for the peak file activity. The hours and minutes are preceded by the day of the month. In this case, 4--11:46 represents October 4 at 11:46 a.m. Because this report can span multiple days, the Performance Manager reports the day as well as the time in this field.
7. The record count indicates the number of Performance data records during the reporting period in which the file is “hot.”
8. The file specification for the hot file. If the file is deleted before the Performance Manager detects its specification, the FID is provided in parentheses instead of its name. All non-virtual QIO activity to the disk is reported under the filespec “(Non Virtual QIO).”