VXVM 6.1 – How to manage VxVM Dynamic Multi Pathing ( DMP) using vxdmpadm?

vxvm-how-toBelow examples will  help you to understand Veritas Dynamic Multipathing administration using vxdmpadm.
To display the usage message for all vxdmpadm commands, enter:
# vxdmpadm help
To obtain a usage message for listctlr, use the command:
# vxdmpadm help listctlr
 
To list all attributes of all HBA controllers on the system, enter:
# vxdmpadm listctlr all
To list all attributes of all the enclosures on the system, enter:
# vxdmpadm listenclosure all
To list all attributes of the disk array enc0, enter:
# vxdmpadm listenclosure enc0
To disable I/O through the HBA controller c2, enter:
# vxdmpadm disable ctlr=c2
If you then run the listctlr all command, the state of the controller c2 is shown as disabled. To enable the HBA controller c2, which was disabled by vxdmpadm disable ctlr=c2, enter:
# vxdmpadm enable ctlr=c2
Executing listctlr all after this command shows the state of the controller c2 as enabled. The following examples outline the attributes supported by vxdmpadm listctlr.
# vxdmpadm listctlr all
# vxdmpadm listctlr type=ENC
# vxdmpadm listctlr enclosure=enc0
# vxdmpadm listctlr ctlr=c2
The following command lists all paths controlled by the DMP node c2t1d0s2.
# vxdmpadm getsubpaths dmpnodename=c2t1d0s2
The following command obtains all paths through the HBA controller c2.
# vxdmpadm getsubpaths ctlr=c2
The following command displays the DMP node that controls the node c3t2d1s2.
# vxdmpadm getdmpnode nodename=c3t2d1s2
The following command displays the DMP nodes connected to the enclosure enc0.
# vxdmpadm getdmpnode enclosure=enc0
The following command assigns a new name, VMGRP_1, to the enclosure enc0.
# vxdmpadm setattr enclosure enc0 name=VMGRP_1
 
To set the policy to check_all, enter:
# vxdmpadm start restore policy=check_all
To start the path restoration thread with the default interval (300 seconds) and default policy (check_disabled), enter:
# vxdmpadm start restore
To specify the interval of polling as 400 seconds, enter:
# vxdmpadm start restore interval=400
The daemon checks the condition of the paths as specified by the policy attribute. To set the policy as check_all, enter:
# vxdmpadm start restore policy=check_all
The following command stops the DMP path restoration thread; the thread is automatically started at system startup time with default attributes.
# vxdmpadm stop restore
If a controller is disabled using the following command, the path restoration thread does not change the disabled state of the path through it.
# vxdmpadm disable ctlr=ctlr
To set the polling interval to 400 seconds, enter:
# vxdmpadm start restore interval=400
Caution: The default polling interval is 300 seconds. Decreasing this interval can adversely affect system performance.
The check_periodic policy can be invoked as follows:
# vxdmpadm start restore policy=check_periodic interval=300 period=15
This example specifies that the DMP path restoration thread checks the status of disabled paths every 300 seconds. The interval is required.
  • The period=15 specifies that the path restoration thread invokes check_disabled fifteen times before check_all is invoked. This repeats.
  • If the integer value n of period is not specified on the command line, it can be set as a tunable dmp_restore_cycles. The value of period specified on the command line takes precedence. If not specified in either of these ways, the default period is 10.
The check_alternate policy can be invoked as follows:
# vxdmpadm start restore policy=check_alternate interval=t
To Set the I/O policy to round-robin for the enclosure SENA0, and to balanced for arrays of type SENA:
# vxdmpadm setattr enclosure SENA0 iopolicy=round-robin
# vxdmpadm setattr arrayname SENA iopolicy=balanced partitionsize=2048
To Set c1t10d0s2 as a standby path:
# vxdmpadm setattr path c1t10d0s2 pathtype=standby
Set c1t20d0s2 as an active path:
# vxdmpadm setattr path c1t20d0s2 pathtype=active
Set c2t20d0s2 as a preferred path with priority 2:
# vxdmpadm setattr path c2t20d0s2 pathtype=preferred priority=2
Reset the priority on path c2t20d0s2:
# vxdmpadm setattr path c2t20d0s2 pathtype=nopreferred
Display operating system device names instead of TPD node names for the enclosure EMC0:
# vxdmpadm setattr enclosure EMC0 tpdmode=native
Enable I/O throttling with a timeout of 400 seconds for all paths to the enclosure enc1:
# vxdmpadm setattr enclosure enc1 recoveryoption=throttle iotimeout=400
Turn off I/O throttling for all paths to the enclosure enc1:
# vxdmpadm setattr enclosure enc1 recoveryoption=nothrottle
Enable time-bound I/O recovery with a timeout of 600 seconds for all paths to the enclosure enc1:
# vxdmpadm setattr enclosure enc1 recoveryoption=timebound iotimeout=600
Display details of the array ports that are configured for the enclosure enc2:
# vxdmpadm getportids enclosure=enc2
Ramdev

Ramdev

I have started unixadminschool.com ( aka gurkulindia.com) in 2009 as my own personal reference blog, and later sometime i have realized that my leanings might be helpful for other unixadmins if I manage my knowledge-base in more user friendly format. And the result is today's' unixadminschool.com. You can connect me at - https://www.linkedin.com/in/unixadminschool/

1 Response

  1. September 18, 2015

    […] Read – How to manage VxVM Dynamic Multi Pathing ( DMP) using vxdmpadm? […]

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