Symantec logo

< Previous  | TOC | Index | Next  >  

Using EMC PowerPath devices with VxVM

In previous versions of VxVM, it was necessary to perform powervxvm init and powervxvm online to use EMC PowerPath devices with VxFAS.

In VxVM 4.0 release, the EMC PowerPath devices can be configured as foreign devices (see the vxddladm(1M) manual page for more information).

In VxVM 4.1 release, the EMC PowerPath devices can be autodiscovered using the third-party driver (TPD) coexistence feature of VxVM. EMC PowerPath devices can still be configured as foreign devices in VxVM 4.1 for VxFAS.

The following sections describe procedures for using PowerPath pseudo (emcpower) devices with VxFAS.

New installation

 Configuring EMC PowerPath devices with foreign device support

If you are not already using EMC PowerPath devices with VxVM, perform the following procedure to put the PowerPath devices under VxVM control as foreign devices:

  1. Make sure that there are no emcpower nodes in /dev/vx/rdmp and /dev/vx/dmp directories. If they exist, remove them.
  2. Install EMC PowerPath software.
  3. Make sure that emcpower devices are present in /dev/rdsk directory.
  4. Disable the DMP Restore daemon:

# /usr/sbin/vxdmpadm stop restore

  1. Exclude the TPD coexistence support for EMC disk array from VxVM.

# /usr/sbin/vxddladm excludearray libname=libvxemc.so

  1. Configure emcpower devices as foreign devices for VxVM: 
            # /usr/sbin/vxddladm addforeign
pathname=/dev/rdsk/emcpower*c
 
            # /usr/sbin/vxddladm addforeign
pathname=/dev/dsk/emcpower*c
  1. Make the emcpower devices visible to VxVM:

# /usr/sbin/vxdisk scandisks

  1. Start the DMP Restore daemon that was previously stopped:

# /usr/sbin/vxdmpadm start restore

  1. Restart the StorageAgent.

 Configuring EMC PowerPath devices with TPD coexistence feature

When upgrading a system to VxVM 4.1, an array support library (ASL) provided by Symantec makes information about any available EMC PowerPath devices available to VxVM. Such devices are configured in DMP as autoconfigured disks with DMP nodes. There is no need to configure these devices as foreign devices any more. See the Veritas Volume Manager Administrator's Guide for more information about TPD coexistence feature of VxVM.

Existing installation of EMC PowerPath devices

If you have already configured emcpower devices for use with VxVM using powervxvm commands, perform the following procedure:

  1. Remove emcpower nodes from /dev/vx/rdmp and /dev/vx/dmp directories:

# /etc/powervxvm remove

  1. Disable the DMP Restore daemon:

# /usr/sbin/vxdmpadm stop restore

  1. Exclude the TPD coexistence support for EMC disk array from VxVM.

# /usr/sbin/vxddladm excludearray libname=libvxemc.so

  1. Configure emcpower devices as foreign devices for VxVM: 
            # /usr/sbin/vxddladm addforeign
pathname=/dev/rdsk/emcpower*c
 
            # /usr/sbin/vxddladm addforeign
pathname=/dev/dsk/emcpower*c
 

 
 
Note
  Alternatively, you can use the TPD coexistence feature of VxVM 4.1 to use EMC PowerPath devices as autoconfigured disks. See Configuring EMC PowerPath devices with TPD coexistence feature.
  1. Make the emcpower devices visible to VxVM:

# /usr/sbin/vxdisk scandisks

  1. Start the DMP Restore daemon that was previously stopped:

# /usr/sbin/vxdmpadm start restore

Using PowerPath native devices

PowerPath native devices can be used by VxVM 4.1 as they are, but you can remove DMP from the I/O path and configure these devices as foreign devices. Refer to Veritas Volume Manager Administator's Guide for more information on foreign device support.

  Note   EMC PowerPath devices must be initialized as simple disks only if they are used as foreign devices. For more information about limitations of foreign devices see Veritas Volume Manager Administator's Guide.

Using VxVM commands

To create a new Volume Manager disk group and add new devices to it, use the vxdg init command: 

    vxdg [-o verify|override] init diskgroup
[medianame=]accessname...

where diskgroup is the Volume Manager disk group. accessname is the device name and medianame is the Volume Manager disk name.

To add new devices to an existing Volume Manager disk group, use the vxdg adddisk command: 

    vxdg -g diskgroup [-o verify|override] adddisk
[medianame=]accessname

For example:

# vxdg -g emcdg adddisk c1t1d1s2

EMC provides a set of rules to ensure that the Volume Manager operates with intelligent storage in an EMC environment. The vxdg command has a verify option that checks that the device being added conforms with the EMC rules. The verify option syntax is:

vxdg -g diskgroup -o verify adddisk accessname

If no EMC rules are broken, vxdg -o verify exits silently and without creating any Volume Manager objects. To create the specified objects, repeat the vxdg command without the -o verify option.

If any of the EMC rules are broken, vxdg -o verify displays a relevant error message and exits without creating any Volume Manager objects. To force Volume Manager to add or create an object that does not comply with the EMC rules, use the -o override option:

vxdg -g diskgroup -o override adddisk accessname

It is not advisable to override the EMC rules as it can result in severe performance degradation or loss of data redundancy. For more details on the EMC rules, see the Overview.

See the Veritas Volume Manager Administrator's Guide or the vxdg(1M) manual page for details on adding devices to the Volume Manager.

 

Notes

  • When a disk is placed under Volume Manager control, the disk is either initialized or encapsulated. Encapsulation preserves existing data on the disk in the form of volumes. Initialization destroys existing data on the disk. Encapsulation is recommended for the root/boot disk and any other disks that contain valuable data. Encapsulation requires a system reboot.
  • Disks that already belong to a disk group cannot be added to another disk group.
  • Disks cannot be added to deported disk groups.
  • The Volume Manager disk name must be unique within the disk group.
  • In an EMC environment, this command may display an error message that indicates that the task or selected disks do not comply with the EMC rules. If you choose to force the Volume Manager to add a disk that does not comply with the EMC rules, the resulting configuration may contain incompatible disks or objects that cannot be administered by VxFAS.
  • In an EMC environment, you cannot mix some device types in a Volume Manager disk group.
  • Encapsulated disks are not supported by VxFAS. Do not encapsulate disks that you plan to include in STD-BCV pairs.
  • For bootdg, all VxFAS functions except restore are supported. See the Veritas Volume Manager Administrator's Guide or the vxdg(1M) manual page for details on how to check the bootdg.
  • If the STD devices in a disk group have attachments, the disk group cannot be destroyed. The disk group can be deported.
  • If one or more NR (not ready) devices were made RW (read-write) without using any toolkit command, you may have to run vxdctl enable to refresh the correct state of the device in VxVM. To check the state of a device (NR or RW), run the sympd list command.
  • VxFAS supports disk group names containing alphanumeric characters, hyphen (-) and underscore (_) only.
  • VxFAS does not support CVM shared disk groups, VxVM SAN disk groups, or disk groups containing VVR replicated volume groups (RVGs).
  • VxFAS supports snapshot operations on CDS type of disk groups. CDS is a license-enabled feature of VxVM and is applied at the disk group level. A CDS disk group is composed only of CDS disks (that is, disks with the VxVM disk format cdsdisk) and its cds attribute set to on.

 ^ Return to Top

< Previous  | TOC | Index | Next  >