Dynamic Multi-Pathing 7.4.1 Administrator's Guide - Linux

Last Published:
Product(s): InfoScale & Storage Foundation (7.4.1)
Platform: Linux
  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. 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 Linux Device Mapper Multipath
    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. 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. 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
  4. 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
      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
  5. 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
    4.  
      Changing the characteristics of a LUN from the array side
    5.  
      Upgrading the array controller firmware online
    6.  
      Reformatting NVMe devices manually
  6. 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
  7. 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
  8. Appendix A. DMP troubleshooting
    1.  
      Recovering from errors when you exclude or include paths to DMP
    2.  
      Downgrading the array support
  9. Appendix B. Reference
    1.  
      Command completion for Veritas commands

Removing LUNs dynamically from an existing target ID

Dynamic Multi-Pathing (DMP) provides a Dynamic Reconfiguration tool to simplify the removal of LUNs from an existing target ID. Each LUN is unmapped from the host. DMP issues an operating system device scan and cleans up the operating system device tree.

Warning:

Do not run any device discovery operations outside of the Dynamic Reconfiguration tool until the device operation is completed.

In a cluster, perform the steps on all nodes in the cluster.

To remove LUNs dynamically from an existing target ID

  1. Stop all applications and volumes that are hosted on the LUNs that are to be removed.

    For LUNs using Linux LVM over DMP devices, remove the device from the LVM volume group.

    # vgreduce vgname
						devicepath
  2. Start the vxdiskadm utility:
    # vxdiskadm
  3. Select the Dynamic Reconfiguration operations option from the vxdiskadm menu.
  4. Select the Remove LUNs option.
  5. Type list or press Return to display a list of LUNs that are available for removal. A LUN is available for removal if it is not in use.

    The following shows an example output:

    Select disk devices to remove: [<pattern-list>,all,list]: list
LUN(s) available for removal:
eva4k6k0_0
eva4k6k0_1
eva4k6k0_2
eva4k6k0_3
eva4k6k0_4
emc0_0119
  6. Enter the name of a LUN, a comma-separated list of LUNs, or a regular expression to specify the LUNs to remove.

    For example, enter emc0_0119.

    Select disk devices to Remove: [<pattern-list>,all,list,
file=<filename>,q] (default:list): emc0_0119
  7. At the prompt, confirm the LUN selection.

    DMP removes the LUN from VxVM usage.

  8. At the following prompt, remove the LUN from the array/target.
    Remove Luns
Menu: VolumeManager/Disk/DynamicReconfigurationOperations/RemoveLuns

INFO: Removing Lun [emc0_0119] from VxVM
INFO: LUN [emc0_0119] removed successfully from VxVM.
-----------------------------------------------------
Enclosure=emc0 AVID=0119
Device=emc0_0119 Serial=2200119000
PATH=sdad ctlr=c11 port=16c-0 [-]
PATH=sdah ctlr=c12 port=16c-0 [-]
PATH=sdaj ctlr=c12 port=16c-1 [-]
PATH=sdaf ctlr=c11 port=16c-1 [-]
-----------------------------------------------------
Please remove LUNs with Above details from array and press 'y' to 
continue removal or 'q' to quit :
  9. The following are sample EMC Symmetrix commands:
    # symmask -sid 822 -wwn 2001000e1ec307de -dir 16c -p 0 remove devs 0119
# symmask -sid 822 -wwn 2001000e1ec307de -dir 16c -p 1 remove devs 0119
# symmask -sid 822 -wwn 2001000e1ec307df -dir 16c -p 0 remove devs 0119
# symmask -sid 822 -wwn 2001000e1ec307df -dir 16c -p 1 remove dev 0119

# symmask -sid 822 refresh -nopr

Symmetrix FA/SE directors updated with contents of SymMask 
Database 000290300822

When complete, respond to previous array prompt.

Please remove LUNs with Above details from array and 
press 'y' to continue removal or 'q' to quit : y
  10. DMP completes the removal of the device from VxVM usage. Output similar to the following is displayed:
    Remove Luns
Menu: VolumeManager/Disk/DynamicReconfigurationOperations/RemoveLuns

INFO: Checking/Removing stale device entries (if any).
INFO: Refreshing OS device Tree
INFO: Updating VxVM device tree
---------------------------------------------------------
Luns Removed
---------------------------------------------------------
emc0_0119
---------------------------------------------------------

Press <Enter> or <Return> to continue:
  11. Specify the dynamic reconfiguration operation to be done:
    Specify Dynamic Reconfiguration Operation to be done:
Menu: VolumeManager/Disk/DynamicReconfigurationOperations

 1	Add Luns
 2	Remove Luns
 3	Replace Luns
 4	Replace HBA


 ?	Display help about menu
 ??	Display help about the menuing system
 q	Exit

    To exit the Dynamic Reconfiguration tool, enter: q