Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 242)

Chapter 12. Troubleshooting
230 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
Available DPM Commands
Drive Performance Monitoring commands are available through the CLI. An
overview of the commands is provided below. For more information about the
command syntax and for examples of the report output, refer to the CLI
Syntax Reference in the 3ware SATA+SAS RAID Controller Card CLI Guide,
Version 10.2.
• Enable DPM . This starts the collection of statistics for drives attached to
your RAID controller. (/cx dpmstat=on).
For efficient collection of data, initiate read/write activity on the specified
controller. The numbers will change over time as the new and old data are
averaged.
• Disable DPM . This stops the collection of statistics. (/cx dpmstat=off)
DPM is disabled by default since there is overhead in maintaining the
statistics. DPM is also disabled following a reboot or power-on. Turning
off DPM does not clear the statistical data that has been recorded. To clear
the data, use the command
/cx/px set dpmstat=clear
[type=ra|lct|ext] .
• Display a DPM Summary . This shows whether DPM is On or Off, and
provides summary statistics for drives attached to a controller.
(/cx show dpmstat)
Note that if DPM is Off, this summary may still show data, although that
data will be static, and not changing over time. Disabling DPM does not
clear the existing data. That is done separately, on a per-port basis (see
below.)
You can also show a subset of summary data, for individual types of
statistics (instantaneous, running average, or extended drive statistics), by
specifying a type attribute with the command.
• Display Specific Drive Statistic . On a per-port basis, you can display
five different statistical reports:
• Instantaneous. This measurement provides a short duration average.
(/cx/px show dpmstat type=inst)
• 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 (/cx/px show dpmstat type=ra)
• Long Command Times. This a collection of the commands with the
longest read/write response time. (/cx/px show dpmstat type=lct
• Histogram Data. The histogram categorizes the read/write execution
times and group them together based on time frames.
(/cx/px show dpmstat type=histdata)
• Extended Drive Statistics. The extended drive statistics refers to
statistics of a drive's read commands, write commands, write