A P P E N D I X A - dsstat and Storage Cache Statistics

A P P E N D I X A

dsstat and Storage Cache Statistics

This appendix describes the operation of the dsstat utility. The dsstat utility collects and reports I/O statistics for the Sun StorageTek Availability Suite software components.

The /usr/sbin/dsstat command displays I/O statistics for the Remote Mirror, Point-in-Time Copy, and Cache software. See the dsstat man page for more information.

Unless you specify otherwise, all fields displayed show per-second averages based on the data collected during the interval. For example, if you specify 5-second intervals, the data displayed is a per-second average of the data collected during the last 5-second interval.

Syntax

dsstat -m mode [-r report-options][-d display-options][-s volume-sets] [-f |-F]
[-z] [interval [count]]

See TABLE A-1 for the command options.

TABLE A-1 `dsstat` Options
Option	Description
`-m` mode	Specifies the statistics reporting mode, where mode is one of the following: `cache` `ii` `sndr` This option determines the options you can use with the `-r` report-option. You cannot use the `-r` report-option if you specify `-m cache`. If `-m` is not specified, the default is for the statistics for all modes to be displayed. You can enter a comma-separated list of modes as well as multiple `-m` switches. The following commands are equivalent: `# dsstat -m sndr,ii` `# dsstat -m sndr -m ii`
`-r` report-options	No report-options are available for the `-m` `cache` mode. If you specify `-m ii`, you can use this option as follows. If you do not specify `-r` report-options, the default display is `-r` `msbo`. `-r m` shows master volume information. `-r s` shows shadow volume information. `-r b` shows bitmap volume information. `-r o` shows overflow volume information (if this volume type is attached). If you specify `-m sndr`, you can use this option as follows. If you do not specify `-r` report-options, the default display is `-r` `bn`. `-r b` shows bitmap volume information (this command shows only the bitmap of the host you are issuing the command from). `-r n` shows network volume information.
`-d` display-options	Specifies the types of information to show. You can specify one or more of the following options on the command line. (If you specify `-d t`, the `r` and `w` options are ignored.) If you specify `-m cache`, the available options are as follows. If you do not specify this option, the default display is `-d` `sf`. `-d r` shows detailed read information. `-d w` shows detailed write information. `-d d` shows destaged data information. `-d c` shows cancelled write information. `-d s` shows summary of information. `-d f` shows cache behavior flags.
	If you specify `-m sndr` or `-m ii`, the available options are as follows. If you do not specify this option, the default display for -m `ii` is `-d` `sf` and for `-m` `sndr` is -d `spf`. `-d r` shows detailed read information. `-d w` shows detailed write information. `-d t` shows timing information. `-d s` shows summary of information. `-d f` shows volume type and status flags. `-d p` shows (`-m` `sndr` only) percentage of volume requiring a synchronization. `-d a` shows (`-m` `sndr` only) shows the secondary volume names.
`-s` volume-set	Shows information about the specified volume-set only. volume-set can also be a comma-delimited list of volume names.
-f -F	Displays a field header for every report cycle. Displays a field header once, when reporting begins.
`-z`	Does not report or display lines that have a value of zero (indicates no activity).
interval [count]	Specifies how often the report is updated. The default interval is one second. count specifies how many reports to display. If count is not specified, report output continues at the specified interval time until you interrupt it by a break (^C). If you do not specify interval and count, the command shows a single report for a one second interval. Unless you specify otherwise, all fields displayed show per second averages based on the data collected during the interval. For example, if you specify 5-second intervals, the data displayed is a per-second average of the data collected during the last 5-second interval.

Examples

TABLE A-2 describes the fields displayed.

Report Cache Statistics

Report cache statistics (dsstat -m cache)

Show detailed information for read and write statistics (-d rw)

Show information for the volume c1t35d0s6 (-s /dev/rdsk/c1t35d0s6)

Generate reports at five-second intervals (5)

Note - Only the trailing sixteen characters of a volume name appear in a report. For example: /dev/rdsk/c1t1d0s0 is displayed as ev/rdsk/c1t1d0s0.

 # dsstat -m cache -d rw -s /dev/rdsk/c1t1d0s0 5

                            - read -             - write -

     volume             ckps   dkps    hit   ckps   dkps    hit

     ev/rdsk/c1t1d0s0      0      0   0.00      0      0   0.00

     ev/rdsk/c1t1d0s0      3   2396   0.13    983    763 100.00

     ev/rdsk/c1t1d0s0   2399    799  75.00   2815   2686 100.00

     ev/rdsk/c1t1d0s0   3200    800  80.00   2755   2908 100.00

     ev/rdsk/c1t1d0s0   3999    799  83.33   2809   2868 100.00

     ev/rdsk/c1t1d0s0   4800    800  85.71   2867   2931 100.00

Report Master and Shadow Volume Point-in-Time Copy Software Statistics

Report master and shadow volume Point-in-Time Copy software statistics
(dsstat -m ii -r ms)

Generate reports at five-second intervals (5).

 # dsstat -m ii -r ms 5

                               - master -      - shadow -

     set name          t  s    kps  tps  svt    kps  tps  svt

     ev/rdsk/c0t1d0s0  I  -      0    0    0      0    0    0

     ev/rdsk/c0t1d0s0  I  -   9047  219    3   9040  219    7

     ev/rdsk/c0t1d0s0  I  -  13548  317    3   9760  243    6

     ev/rdsk/c0t1d0s0  I  -   5946  155    3   9684  227    8

     ev/rdsk/c0t1d0s0  I  -  16539  417    2   9242  225    7

Report Network Statistics for the Remote Mirror Software

Reports network statistics for the Remote Mirror software (-m sndr, -r n)

Shows information for the secondary volume c1t35d0s6(-s /dev/rdsk/c1t35d0s6)

Shows detailed information for read and write statistics, timing, and volume type or status flags (-d rwtf)

Generates reports at five-second intervals (5)

 # dsstat -m sndr -r n -d rwtpf -s /dev/rdsk/c1t1d0s0 5

                                           - network -

     set name          t  s     sn   rkps rtps   wkps wtps  svt

     ev/rdsk/c1t1d0s0  P  L  77.27      0    0      0    0    0

     ev/rdsk/c1t1d0s0  P SY  75.07      0    0   2317   72   11

     ev/rdsk/c1t1d0s0  P SY  71.67      0    0   3443  108    9

     ev/rdsk/c1t1d0s0  P SY  69.37      0    0   2426   76   12

     ev/rdsk/c1t1d0s0  P SY  66.68      0    0   2765   86   11

TABLE A-2 `dsstat` Display Fields
Field	Description
`set name`	Volume set specified by `-s` option
`t`	Volume type for remote mirror volumes: `P` primary host volume `S` secondary host volume Volume type for the point-in-time copy volumes: `I` independent shadow volume set `D` dependent shadow volume set Valid cache modes: `C` cache reads and writes `D` disk reads and writes
`s`	Volume status for the Remote Mirror software: `L` volume is in logging mode; changes are being logged R replicating changes to secondary `SY` forward synchronization is in progress `RS` reverse synchronization is in progress `SN` forward synchronization needed `RN` reverse synchronization needed `VF` volume failed `BF` bitmap failed Volume status for the point-in-time copy volumes: `C` copy in progress `-` no copy in progress
`sn`	Percentage of volume requiring sync
`rtps`	Number of reads
`rkps`	Kilobytes read
`wtps`	Number of writes
`wkps`	Kilobytes written
`svt`	Service time per operation
`tps`	Sum of `rtps` and `wtps`
`kps`	Sum of `rkps` and `wkps`
`r`	Cache read behavior
`w`	Cache write behavior
`ckps`	Kilobytes read from cache
`dkps`	Kilobytes read from disk
`hit`	Read hits during interval
`ds/s`	Kilobytes destaged from cache
`cn/s`	Number of write cancellations