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

Displaying extended device attributes

Device Discovery Layer (DDL) extended attributes are attributes or flags corresponding to a Veritas Volume Manager (VxVM) or Dynamic Multi-Pathing (DMP) LUN or disk and that are discovered by DDL. These attributes identify a LUN to a specific hardware category.

Table: Categories for extended attributes describes the list of categories.

Table: Categories for extended attributes

Category

Description

Hardware RAID types

Displays what kind of Storage RAID Group the LUN belongs to

Thin Provisioning Discovery and Reclamation

Displays the LUN's thin reclamation abilities

Device Media Type

Displays the type of media - whether SSD (Solid State Drive)

Storage-based Snapshot/Clone

Displays whether the LUN is a SNAPSHOT or a CLONE of a PRIMARY LUN

Storage-based replication

Displays if the LUN is part of a replicated group across a remote site

Transport

Displays what kind of HBA is used to connect to this LUN (FC, SATA, iSCSI)

Each LUN can have one or more of these extended attributes. DDL discovers the extended attributes during device discovery from the Array Support Library (ASL). If Veritas Operations Manager (VOM) is present, DDL can also obtain extended attributes from the VOM Management Server for hosts that are configured as managed hosts.

The vxdisk -p list command displays DDL extended attributes. For example, the following command shows attributes of std, fc, and RAID_5 for this LUN: 

# vxdisk -p list
DISK           : tagmastore-usp0_0e18
DISKID         : 1253585985.692.rx2600h11
VID            : HITACHI
UDID           : HITACHI%5FOPEN-V%5F02742%5F0E18
REVISION       : 5001
PID            : OPEN-V
PHYS_CTLR_NAME : 0/4/1/1.0x50060e8005274246
LUN_SNO_ORDER  : 411
LUN_SERIAL_NO  : 0E18
LIBNAME        : libvxhdsusp.sl
HARDWARE_MIRROR: no
DMP_DEVICE     : tagmastore-usp0_0e18
DDL_THIN_DISK  : thick
DDL_DEVICE_ATTR: std fc RAID_5
CAB_SERIAL_NO  : 02742
ATYPE          : A/A
ARRAY_VOLUME_ID: 0E18
ARRAY_PORT_PWWN: 50:06:0e:80:05:27:42:46
ANAME          : TagmaStore-USP
TRANSPORT      : FC

The vxdisk -x attribute -p list command displays the one-line listing for the property list and the attributes. The following example shows two Hitachi LUNs that support Thin Reclamation through the attribute hdprclm:

# vxdisk -x DDL_DEVICE_ATTR -p list 
DEVICE                  DDL_DEVICE_ATTR 
tagmastore-usp0_0a7a    std fc RAID_5 
tagmastore-usp0_065a    hdprclm fc 
tagmastore-usp0_065b    hdprclm fc

User can specify multiple -x options in the same command to display multiple entries. For example: 

# vxdisk -x DDL_DEVICE_ATTR -x VID -p list 
DEVICE               DDL_DEVICE_ATTR  VID        
tagmastore-usp0_0a7a std fc RAID_5    HITACHI      
tagmastore-usp0_0a7b std fc RAID_5    HITACHI      
tagmastore-usp0_0a78 std fc RAID_5    HITACHI
tagmastore-usp0_0a79 std fc RAID_5    HITACHI
tagmastore-usp0_065a hdprclm fc       HITACHI
tagmastore-usp0_065b hdprclm fc       HITACHI
tagmastore-usp0_065c hdprclm fc       HITACHI
tagmastore-usp0_065d hdprclm fc       HITACHI

Use the vxdisk -e list command to show the DLL_DEVICE_ATTR property in the last column named ATTR.

# vxdisk -e list 
DEVICE 	            	TYPE 	DISK 	GROUP 	STATUS 	OS_NATIVE_NAME 	ATTR 
tagmastore-usp0_0a7a auto  -     -      online  c10t0d2      	  std fc RAID_5 
tagmastore-usp0_0a7b auto  -     -      online  c10t0d3      	  std fc RAID_5 
tagmastore-usp0_0a78 auto  -     -      online  c10t0d0      	  std fc RAID_5 
tagmastore-usp0_0655 auto  -     -      online  c13t2d7      	  hdprclm fc 
tagmastore-usp0_0656 auto  -     -      online  c13t3d0      	  hdprclm fc 
tagmastore-usp0_0657 auto  -     -      online  c13t3d1      	  hdprclm fc

For a list of ASLs that supports Extended Attributes, and descriptions of these attributes, refer to the hardware compatibility list (HCL) at the following URL:

https://www.veritas.com/support/en_US/article.000126344