To increase the level of logging for DMP, it will be necessary to set the required level of the VxDMP tunable for dmp_log_level by using the vxdmpadm command as explained below:

Setting this tunable defines the level of detail to which DMP console messages are displayed. The following level values are defined:

1. Display critical DMP log messages.  This is the default setting.
2. Display  level  1  messages  plus  messages that relate to I/O throttling, suspected path failures, repeated path failures and DMP node migration.
3. Display level 1 and 2 messages plus messages that relate to I/O errors, I/O error analysis and path media errors.
4. Display level 1, 2 and 3 messages plus messages that relate to setting or changing attributes.

To check the current setting and level for dmp_log_level:

# vxdmpadm gettune dmp_log_level
         Tunable                   Current Value      Default Value
------------------------------         -------------             -------------
dmp_log_level                             1                          1

Now to set the dmp_log_level to a desired level, the following command can be run:

For example, to set the dmp_log_level to level 4 execute the command as:

# vxdmpadm settune dmp_log_level=4

Tunable value will be changed immediately

Now verify that the tuning has been updated:

# vxdmpadm gettune dmp_log_level
            Tunable                 Current Value     Default Value
------------------------------         -------------            -------------
dmp_log_level                             4                        1

The dmp logs are stored in the dmpevents logs located in the /etc/vx/ directory.

# tail -f /etc/vx/dmpevents.log
Tunable value will be changed immediately
Fri Jan 21 09:43:33.000: Initiated SAN topology discovery
Fri Jan 21 09:43:33.000: Completed SAN topology discovery
Fri Jan 21 09:43:38.000: Initiated SAN topology discovery
Fri Jan 21 09:43:38.000: Completed SAN topology discovery
Fri Jan 21 09:43:43.000: Initiated SAN topology discovery
Fri Jan 21 09:43:43.000: Completed SAN topology discovery
Fri Jan 21 09:43:48.000: Initiated SAN topology discovery

Once the outputs have been collected as requested by Technical Support for troubleshooting purposes, it would be appropriate to set the log level to the defaults once again:

# vxdmpadm settune dmp_log_level=1

Tunable value will be changed immediately

Now verify that the tuning has been updated to the default values:

# vxdmpadm gettune dmp_log_level
            Tunable               Current Value  Default Value
------------------------------    -------------  -------------
dmp_log_level                             1                1