Did you know tw_cli has performance monitoring??

Yep title says it all, you can actually monitor individual disk performance with tw_cli.

First we need to enable performance monitoring:

tw_cli /c0 set dpmstat=on

Now we will show the information its providing.

tw_cli /c0 show dpmstat  type=ra
Drive Performance Monitor Configuration for /c0 ...
Performance Monitor: ON
Version: 1
Max commands for averaging: 100
Max latency commands to save: 10
Requested data: Running Average Drive Statistics

 Queue           Xfer         Resp
Port   Status           Unit   Depth   IOPs    Rate(MB/s)   Time(ms)
p0     OK               u0     22      23      0.479        11
p1     OK               u0     24      93      1.344        12
p2     OK               u0     25      82      0.720        14
p3     OK               u0     24      83      1.108        16


tw_cli /c0 set dpmstat=off

Different performance results:

This command only applies to 9000 series SX/SE/SA controllers, except for
type=ext, which applies only to SE/SA models.

This command allows you to request drive statistics of the specified type for
the specified port. These statistics can be helpful when troubleshooting
performance problems.

type= specifies which statistics should be displayed. The options are: inst for
Instantaneous, ra for Running Average, lct for Long Command Times,
histdata for Histogram Data, and ext for Extended Drive Statistics.

inst (Instantaneous). This measurement provides a short duration average.
ra (Running Average). Running average is a measure of long-term averages
that smooth out the data, and results in older results fading from the average
over time.

ext (Extended Drive Statistics). The extended drive statistics refers to
statistics of a drive’s read commands, write commands, write commands with
FUA (Force Unit Access), flush commands, and a drive sectors’s read, write,
and write commands with FUA.

lct (Long Command Times). This a collection of the commands with the
longest read/write response time.

histdata (Histogram Data). The histogram categorizes the read/write
execution times and group them together based on time frames.

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