Dynamic Multi-Pathing 8.0.1 Administrator's Guide - Windows

Last Published:
Product(s): InfoScale & Storage Foundation (8.0.1)
Platform: Windows
  1. Understanding DMPW
    1.  
      DMP overview
    2.  
      Major features of Dynamic Multi-Pathing
    3. How DMP works
      1. How DMP monitors I/O on paths
        1.  
          Path failover mechanism
      2.  
        Load balancing
      3.  
        DMP in a clustered environment
    4.  
      Multiple paths to disk arrays
    5.  
      Device discovery
  2. Setting up DMPW
    1.  
      Active/Active and Active/Passive settings
    2. Active/Active and Active/Passive settings in a cluster environment
      1.  
        DMP DSMs
      2.  
        SCSI-3 PGR technology
      3.  
        Enabling SCSI-3 PGR
    3. Add and remove paths
      1.  
        Adding a path
      2.  
        Removing a path
    4. Specify load balancing settings and the primary path
      1.  
        Specifying load balancing settings for an array
      2.  
        Specifying load balancing settings for a disk
      3.  
        Specifying the primary path for an array or disk
    5. Configuring DSMs without storage connection
      1.  
        Specify DSM settings without storage connection
  3. Administering DMPW
    1.  
      About administering DMP
    2. DMP DSMs menus
      1.  
        Displaying the menu for arrays
      2.  
        Commands for arrays
      3.  
        Displaying the menu for disks
      4.  
        Commands for paths of a disk
      5.  
        Statistics monitoring
      6.  
        Clear performance statistics
      7.  
        Device settings
      8.  
        Set primary path
      9.  
        Properties
    3. View array, disk, and path status
      1.  
        Array status
      2.  
        Device status
      3.  
        Path status
    4. vxdmpadm
      1.  
        vxdmpadm dsminfo
      2.  
        vxdmpadm arrayinfo
      3.  
        vxdmpadm deviceinfo
      4.  
        vxdmpadm pathinfo
      5.  
        vxdmpadm arrayperf
      6.  
        vxdmpadm deviceperf
      7.  
        vxdmpadm pathperf
      8.  
        vxdmpadm allperf
      9.  
        vxdmpadm iostat
      10.  
        vxdmpadm cleardeviceperf
      11.  
        vxdmpadm cleararrayperf
      12.  
        vxdmpadm clearallperf
      13.  
        vxdmpadm setdsmscsi3
      14.  
        vxdmpadm setarrayscsi3
      15.  
        vxdmpadm setattr dsm
      16.  
        vxdmpadm setattr array
      17.  
        vxdmpadm setattr device
      18.  
        vxdmpadm setattr path
      19.  
        vxdmpadm set isislog
      20.  
        vxdmpadm rescan
      21.  
        vxdmpadm disk list
      22.  
        vxdmpadm getdsmattrib
      23.  
        vxdmpadm getmpioparam
      24.  
        vxdmpadm setmpioparam
  4. Performance tuning
    1.  
      Specifying control timer settings for an array
  5. Troubleshooting
    1. Resolving DMP issues
      1.  
        When a DMP license is no longer valid
      2.  
        When an unknown disk group appears in a DMP environment
    2. Using status information
      1.  
        Path status
      2.  
        Path states
  6. Glossary
    1.  
      Dynamic Multi-Pathing glossary

Load balancing

DMP also provides balancing of I/O load traffic, thereby improving system and application performance. Load balancing maximizes I/O throughput by using the total bandwidth of all available paths. Depending on different load balancing policies, appropriate path is selected to send down the I/O to the LUN.

For information on the load balancing policies available under the Active/Active configuration:

See Active/Active and Active/Passive settings.

For information on specifying the load balancing settings for the paths in an array and for individual disks:

See Specify load balancing settings and the primary path.

For Active/Passive disk arrays, I/O is sent down the primary path. If the primary path fails, I/O is switched over to the other available primary paths or secondary paths. As the continuous transfer of ownership of LUNs from one controller to another results in severe I/O slowdown, load balancing across paths is not performed for Active/Passive disk arrays unless they support concurrent I/O. Both paths of an Active/Passive array are not considered to be on different controllers when mirroring across controllers. For A/P, A/PF and A/PG arrays, load balancing is performed across all the currently active paths as is done for Active/Active arrays. You can use the vxdmpadm command or the VEA GUI to change the I/O policy for the paths to an enclosure or disk array.