Dynamic Multi-Pathing 7.3.1 Administrator's Guide - Linux

Last Published:
Product(s): InfoScale & Storage Foundation (7.3.1)
  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

Getting or setting the iSCSI operational parameters

DDL provides an interface to set and display certain parameters that affect the performance of the iSCSI device path. However, the underlying OS framework must support the ability to set these values. The vxddladm set command returns an error if the OS support is not available.

Table: Parameters for iSCSI devices

Parameter

Default value

Minimum value

Maximum value

DataPDUInOrder

yes

no

yes

DataSequenceInOrder

yes

no

yes

DefaultTime2Retain

20

0

3600

DefaultTime2Wait

2

0

3600

ErrorRecoveryLevel

0

0

2

FirstBurstLength

65535

512

16777215

InitialR2T

yes

no

yes

ImmediateData

yes

no

yes

MaxBurstLength

262144

512

16777215

MaxConnections

1

1

65535

MaxOutStandingR2T

1

1

65535

MaxRecvDataSegmentLength

8182

512

16777215

To get the iSCSI operational parameters on the initiator for a specific iSCSI target

  • Type the following commands:
    # vxddladm getiscsi target=tgt-id {all | parameter}

    You can use this command to obtain all the iSCSI operational parameters. 

    # vxddladm getiscsi target=c2_p2_t0

    The following is a sample output:

    PARAMETER              CURRENT  DEFAULT    MIN      MAX
--------------------------------------------------------
DataPDUInOrder          	  yes     yes      no      yes
DataSequenceInOrder     	  yes     yes      no      yes
DefaultTime2Retain      	   20      20       0     3600
DefaultTime2Wait        		   2       2       0     3600
ErrorRecoveryLevel      		   0       0       0        2
FirstBurstLength       		65535	  65535	    512 16777215
InitialR2T              	  yes     yes     	no      yes
ImmediateData           	  yes     yes     	no      yes
MaxBurstLength          262144  262144     512 16777215
MaxConnections          	    1       1       1    65535
MaxOutStandingR2T           	1       1       1    65535
MaxRecvDataSegmentLength  8192     8182 	  512 16777215

To set the iSCSI operational parameters on the initiator for a specific iSCSI target

  • Type the following command:
    # vxddladm setiscsi target=tgt-id parameter=value