Evaluate Performance in Detail › Histograms › Image Residence Histograms › Disk I/O Per Second Histogram

Disk I/O Per Second Histogram

The following example shows a disk I/O per second histogram:

Histograms                      DEMAND (VAX 8700)                       Page   7
	PA Vx.x
					Tuesday 06-SEP-2005 00:00 to 23:59

                                                            *---------------*
                                                            |    Legend: 1  |
                                                            |               |
                                                            | * user io     |
                             DISK I/O PER SECOND            | P pag+swping  |
IOs per sec  2               -------------------            *---------------*
150 !
145 !
100 !
 95 !
 90 !
 85 !
 80 !
 75 !
 70 !
 65 !
 60 !
 55 !
 50 !
 45 !
 40 !
 35 !                                  **
 30 !                                  **
 25 !       *                          **   * **
 20 !       *                      ****PP** * **  *  *
 15 !       *                 *  * ****PP***P*P**** *****
 10 !       P*                *****PP*PPPPP*PPPPPPP*PPPP** *** *
  5 ! *P*P**PPPP****P**PP*PPP*PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP*P**PP*PPPP
    ! ---01-02-03-04-05-06-07-08-09-10-11-12-13-14-15-16-17-18-19-20-21-22-23-
                                                                             3
        Each Column represents approximately 20 minutes starting from
        6-SEP 00:00:00 to  6-SEP 23:59:00.  An "N" indicates NO DATA.

The following statements are keyed to the previous example:

1. Explanatory list of units in the histogram columns.
2. The number of disk I/Os per second attributable to either user I/O or paging and swapping.
3. Number of hours spanned by the reporting period. This histogram reflects a reporting period of 24 hours.