Dynamic Multi-Pathing 7.4.1 Administrator's Guide - AIX

Last Published:
Product(s): InfoScale & Storage Foundation (7.4.1)
Platform: AIX
  1. Understanding DMP
    1.  
      About Dynamic Multi-Pathing (DMP)
    2. How DMP works
      1. How DMP monitors I/O on paths
        1.  
          Path failover mechanism
        2.  
          Subpaths Failover Group (SFG)
        3.  
          Low Impact Path Probing (LIPP)
        4.  
          I/O throttling
      2.  
        Load balancing
      3.  
        Using DMP with LVM boot disks
      4.  
        Disabling MPIO
      5. DMP in a clustered environment
        1.  
          About enabling or disabling controllers with shared disk groups
    3.  
      Multi-controller ALUA support
    4.  
      Multiple paths to disk arrays
    5.  
      Device discovery
    6.  
      Disk devices
    7. Disk device naming in DMP
      1.  
        About operating system-based naming
      2. About enclosure-based naming
        1.  
          Summary of enclosure-based naming
        2.  
          Enclosure based naming with the Array Volume Identifier (AVID) attribute
  2. Setting up DMP to manage native devices
    1.  
      About setting up DMP to manage native devices
    2.  
      Displaying the native multi-pathing configuration
    3.  
      Migrating LVM volume groups to DMP
    4.  
      Migrating to DMP from EMC PowerPath
    5.  
      Migrating to DMP from Hitachi Data Link Manager (HDLM)
    6.  
      Migrating to DMP from IBM Multipath IO (MPIO) or MPIO path control module (PCM)
    7. Using Dynamic Multi-Pathing (DMP) devices with Oracle Automatic Storage Management (ASM)
      1.  
        Enabling Dynamic Multi-Pathing (DMP) devices for use with Oracle Automatic Storage Management (ASM)
      2.  
        Removing Dynamic Multi-Pathing (DMP) devices from the listing of Oracle Automatic Storage Management (ASM) disks
      3.  
        Migrating Oracle Automatic Storage Management (ASM) disk groups on operating system devices to Dynamic Multi-Pathing (DMP) devices
    8.  
      Adding DMP devices to an existing LVM volume group or creating a new LVM volume group
    9.  
      Removing DMP support for native devices
  3. Dynamic Multi-Pathing for the Virtual I/O Server
    1.  
      About Dynamic Multi-Pathing in a Virtual I/O server
    2.  
      About the Volume Manager (VxVM) component in a Virtual I/O server
    3. Configuring Dynamic Multi-Pathing (DMP) on Virtual I/O server
      1.  
        Virtual I/O Server (VIOS) requirements
      2.  
        Migrating from other multi-pathing solutions to DMP on Virtual I/O server
      3.  
        Migrating from MPIO to DMP on a Virtual I/O server for a dual-VIOS configuration
      4.  
        Migrating from PowerPath to DMP on a Virtual I/O server for a dual-VIOS configuration
    4. Configuring Dynamic Multi-Pathing (DMP) pseudo devices as virtual SCSI devices
      1.  
        Exporting Dynamic Multi-Pathing (DMP) devices as virtual SCSI disks
      2.  
        Exporting a Logical Volume as a virtual SCSI disk
      3.  
        Exporting a file as a virtual SCSI disk
    5. Extended attributes in VIO client for a virtual SCSI disk
      1.  
        Configuration prerequisites for providing extended attributes on VIO client for virtual SCSI disk
      2.  
        Displaying extended attributes of virtual SCSI disks
  4. Administering DMP
    1.  
      About enabling and disabling I/O for controllers and storage processors
    2.  
      About displaying DMP database information
    3.  
      Displaying the paths to a disk
    4.  
      Setting customized names for DMP nodes
    5. Configuring DMP for SAN booting
      1.  
        Configuring DMP support for booting over a SAN
      2.  
        Migrating an internal root disk to a SAN root disk under DMP control
      3.  
        Migrating a SAN root disk from MPIO to DMP control
      4.  
        Migrating a SAN root disk from EMC PowerPath to DMP control
    6. Administering the root volume group (rootvg) under DMP control
      1.  
        Running the bosboot command when LVM rootvg is enabled for DMP
      2. Extending an LVM rootvg that is enabled for DMP
        1.  
          Extending an LVM rootvg when dmp_native_support is on
        2.  
          Extending an LVM rootvg when dmp_native_support is off
      3.  
        Reducing the native rootvg that is enabled for DMP
      4.  
        Mirroring the root volume group
      5.  
        Removing the mirror for the root volume group (rootvg)
      6.  
        Cloning a LVM rootvg that is enabled for DMP
      7.  
        Cleaning up the alternate disk volume group when LVM rootvg is enabled for DMP
      8.  
        Using mksysb when the root volume group is under DMP control
      9.  
        Upgrading Dynamic Multi-Pathing and AIX on a DMP-enabled rootvg
    7. Using Storage Foundation in the logical partition (LPAR) with virtual SCSI devices
      1.  
        Setting up DMP for vSCSI devices in the logical partition (LPAR)
      2.  
        About disabling DMP for vSCSI devices in the logical partition (LPAR)
      3.  
        Preparing to install or upgrade Storage Foundation with DMP disabled for vSCSI devices in the logical partition (LPAR)
      4.  
        Disabling DMP multi-pathing for vSCSI devices in the logical partition (LPAR) after installation or upgrade
      5.  
        Adding and removing DMP support for vSCSI devices for an array
      6. How DMP handles I/O for vSCSI devices
        1.  
          Setting the vSCSI I/O policy
    8.  
      Running alt_disk_install, alt_disk_copy and related commands on the OS device when DMP native support is enabled
    9. Administering DMP using the vxdmpadm utility
      1.  
        Retrieving information about a DMP node
      2.  
        Displaying consolidated information about the DMP nodes
      3.  
        Displaying the members of a LUN group
      4.  
        Displaying paths controlled by a DMP node, controller, enclosure, or array port
      5.  
        Displaying information about controllers
      6.  
        Displaying information about enclosures
      7.  
        Displaying information about array ports
      8.  
        User-friendly CLI outputs for ALUA arrays
      9.  
        Displaying information about devices controlled by third-party drivers
      10.  
        Displaying extended device attributes
      11.  
        Suppressing or including devices from VxVM control
      12. Gathering and displaying I/O statistics
        1.  
          Displaying cumulative I/O statistics
        2.  
          Displaying statistics for queued or erroneous I/Os
        3.  
          Examples of using the vxdmpadm iostat command
      13.  
        Setting the attributes of the paths to an enclosure
      14.  
        Displaying the redundancy level of a device or enclosure
      15.  
        Specifying the minimum number of active paths
      16.  
        Displaying the I/O policy
      17. Specifying the I/O policy
        1.  
          Scheduling I/O on the paths of an Asymmetric Active/Active or an ALUA array
        2.  
          Example of applying load balancing in a SAN
      18.  
        Disabling I/O for paths, controllers, array ports, or DMP nodes
      19.  
        Enabling I/O for paths, controllers, array ports, or DMP nodes
      20.  
        Renaming an enclosure
      21.  
        Configuring the response to I/O failures
      22.  
        Configuring the I/O throttling mechanism
      23.  
        Configuring Subpaths Failover Groups (SFG)
      24.  
        Configuring Low Impact Path Probing (LIPP)
      25.  
        Displaying recovery option values
      26.  
        Configuring DMP path restoration policies
      27.  
        Stopping the DMP path restoration thread
      28.  
        Displaying the status of the DMP path restoration thread
      29.  
        Configuring Array Policy Modules
  5. Administering disks
    1.  
      About disk management
    2. Discovering and configuring newly added disk devices
      1.  
        Partial device discovery
      2. About discovering disks and dynamically adding disk arrays
        1.  
          How DMP claims devices
        2.  
          Disk categories
        3.  
          Adding DMP support for a new disk array
        4.  
          Enabling discovery of new disk arrays
        5.  
          Discovering renamed devices on AIX
      3.  
        About third-party driver coexistence
      4. How to administer the Device Discovery Layer
        1.  
          Listing all the devices including iSCSI
        2.  
          Listing all the Host Bus Adapters including iSCSI
        3.  
          Listing the ports configured on a Host Bus Adapter
        4.  
          Listing the targets configured from a Host Bus Adapter or a port
        5.  
          Listing the devices configured from a Host Bus Adapter and target
        6.  
          Getting or setting the iSCSI operational parameters
        7.  
          Listing all supported disk arrays
        8.  
          Excluding support for a disk array library
        9.  
          Re-including support for an excluded disk array library
        10.  
          Listing excluded disk arrays
        11.  
          Listing disks claimed in the DISKS category
        12.  
          Displaying details about an Array Support Library
        13.  
          Adding unsupported disk arrays to the DISKS category
        14.  
          Removing disks from the DISKS category
        15.  
          Foreign devices
    3. Changing the disk device naming scheme
      1.  
        Displaying the disk-naming scheme
      2.  
        Regenerating persistent device names
      3.  
        Changing device naming for enclosures controlled by third-party drivers
    4.  
      Discovering the association between enclosure-based disk names and OS-based disk names
  6. Dynamic Reconfiguration of devices
    1.  
      About online Dynamic Reconfiguration
    2. Reconfiguring a LUN online that is under DMP control using the Dynamic Reconfiguration tool
      1.  
        Removing LUNs dynamically from an existing target ID
      2.  
        Adding new LUNs dynamically to a target ID
      3.  
        Replacing LUNs dynamically from an existing target ID
      4.  
        Replacing a host bus adapter online
    3. Manually reconfiguring a LUN online that is under DMP control
      1.  
        Overview of manually reconfiguring a LUN
      2.  
        Manually removing LUNs dynamically from an existing target ID
      3.  
        Manually adding new LUNs dynamically to a new target ID
      4.  
        About detecting target ID reuse if the operating system device tree is not cleaned up
      5.  
        Scanning an operating system device tree after adding or removing LUNs
      6.  
        Manually cleaning up the operating system device tree after removing LUNs
      7.  
        Manually replacing a host bus adapter online
    4.  
      Changing the characteristics of a LUN from the array side
    5.  
      Upgrading the array controller firmware online
  7. Event monitoring
    1.  
      About the Dynamic Multi-Pathing (DMP) event source daemon (vxesd)
    2.  
      Fabric Monitoring and proactive error detection
    3.  
      Dynamic Multi-Pathing (DMP) discovery of iSCSI and SAN Fibre Channel topology
    4.  
      DMP event logging
    5.  
      Starting and stopping the Dynamic Multi-Pathing (DMP) event source daemon
  8. Performance monitoring and tuning
    1.  
      About tuning Dynamic Multi-Pathing (DMP) with templates
    2.  
      DMP tuning templates
    3.  
      Example DMP tuning template
    4.  
      Tuning a DMP host with a configuration attribute template
    5.  
      Managing the DMP configuration files
    6.  
      Resetting the DMP tunable parameters and attributes to the default values
    7.  
      DMP tunable parameters and attributes that are supported for templates
    8.  
      DMP tunable parameters
    9.  
      DMP driver tunables
  9. Appendix A. DMP troubleshooting
    1.  
      Displaying extended attributes after upgrading to DMP 7.4.1
    2.  
      Recovering from errors when you exclude or include paths to DMP
    3.  
      Downgrading the array support
  10. Appendix B. Reference
    1.  
      Command completion for Veritas commands

Exporting Dynamic Multi-Pathing (DMP) devices as virtual SCSI disks

DMP supports disks backed by DMP as virtual SCSI disks. Export the DMP device as a vSCSI disk to the VIO client.

To export a DMP device as a vSCSI disk

  1. Log into the VIO server partition.
  2. Use the following command to access the non-restricted root shell. All subsequent commands in this procedure must be invoked from the non-restricted shell. 
    $ oem_setup_env
  3. The following command displays the DMP devices on the VIO server:
    dmpvios1$ lsdev -t dmpdisk
    ibm_ds8000_0287 Available  Veritas DMP Device
ibm_ds8000_0288 Available  Veritas DMP Device
ibm_ds8000_0292 Available  Veritas DMP Device
ibm_ds8000_0293 Available  Veritas DMP Device
ibm_ds8000_029a Available  Veritas DMP Device
ibm_ds8000_02c1 Available  Veritas DMP Device
ibm_ds8000_0337 Available  Veritas DMP Device
  4. Assign the DMP device as a backing device. Exit from the non-restricted shell to run this command from the VIOS default shell. 
    dmpvios1$ exit
    $ mkvdev -vdev ibm_ds8000_0288 -vadapter vhost0
vtscsi3 Available
  5. Use the following command to display the configuration.
    $ lsmap -all
    SVSA           Physloc                    Client Partition ID 
-------------- -------------------------- ------------------- 
vhost0         U9117.MMA.0686502-V2-C11   0x00000000 
VTD              vtscsi0 
Status           Available 
LUN              0x8100000000000000 
Backing device   ibm_ds8000_0337 
Physloc 

VTD              vtscsi1 
Status           Available 
LUN              0x8200000000000000 
Backing device   ibm_ds8000_02c1 
Physloc 

VTD              vtscsi2 
Status           Available 
LUN              0x8300000000000000 
Backing device   ibm_ds8000_029a 
Physloc V

TD               vtscsi3 
Status           Available 
LUN              0x8400000000000000 
Backing device   ibm_ds8000_0288 
Physloc
  6. For a dual-VIOS configuration, export the DMP device corresponding to the same SAN LUN on the second VIO Server in the configuration. To export the DMP device on the second VIO server, identify the DMP device corresponding to the SAN LUN as on the VIO Server1.

    • If the array supports the AVID attribute, the DMP device name is the same as the DMP device name on the VIO Server1.

    • Otherwise, use the UDID value of the DMP device on the VIO Server1 to correlate the DMP device name with same UDID on the VIO Server2.

      On VIO Server1:

      $ oem_setup_env
      dmpvios1$ lsattr -El ibm_ds8000_0288
      attribute value            description        user_settable 
dmpname   ibm_ds8x000_0288 DMP Device name   True 
pvid      none             Physical volume identifier True 
unique_id IBM%5F2107%5F75MA641%5F6005076308FFC61A000000000
0000288 
Unique device identifier   True

      On VIO Server2:

      $ oem_setup_env
      dmpvios2$ odmget -q "attribute = unique_id and 
value = 'IBM%5F2107%5F75MA641%5F6005076308FFC61A000000000
0000288'" CuAt
      CuAt: 

   name = "ibm_ds8000_0288"
   attribute = "unique_id"
   value = "IBM%5F2107%5F75MA641%5F6005076308FFC61A00
   00000000000288" 
   type = "R" 
   generic = "DU"
   rep = "s" 
   nls_index = 4
  7. Use the DMP device name identified in step 6 to assign the DMP device as a backing device. Exit from the non-restricted shell to run this command from the VIOS default shell. 
    dmpvios1$ exit
    $ mkvdev -vdev ibm_ds8000_0288 -vadapter vhost0
vtscsi3 Available
  8. Use the following command to display the configuration.
    $ lsmap -all
    SVSA           Physloc                   Client Partition ID 
-------------- ------------------------- ------------------- 
vhost0         U9117.MMA.0686502-V2-C11  0x00000000 
VTD              vtscsi0 
Status           Available 
LUN              0x8100000000000000 
Backing device   ibm_ds8000_0337 
Physloc 

VTD              vtscsi1 
Status           Available 
LUN              0x8200000000000000 
Backing device   ibm_ds8000_02c1 
Physloc 

VTD              vtscsi2 
Status           Available 
LUN              0x8300000000000000 
Backing device   ibm_ds8000_029a 
Physloc V

TD               vtscsi3 
Status           Available 
LUN              0x8400000000000000 
Backing device   ibm_ds8000_0288 
Physloc