Setting up shared storage: SCSI

Article:HOWTO77040  |  Created: 2012-05-22  |  Updated: 2012-05-24  |  Article URL http://www.symantec.com/docs/HOWTO77040
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Setting up shared storage: SCSI

Perform the following steps to set up shared storage.

Figure: Cabling the shared storage

Cabling the shared storage

On AIX:

SCSI adapters are typically set with a default identifier value of 7. Each device on a SCSI bus must have a unique SCSI identifier value. When more than one system is connected to a SCSI bus, you must change the SCSI identifier to a unique number. You must make this change to one or more systems, usually the unique number is 5 or 6.

Perform the procedure if you want to connect to shared storage with shared SCSI devices.

To set the SCSI identifier value on AIX

  1. Determine the SCSI adapters on each system:

    north # lsdev -C -c adapter | grep scsi
    scsi0   Available 11-08    Wide/Ultra-2 SCSI I/O Controller
    scsi1   Available 11-09    Wide/Ultra-2 SCSI I/O Controller
    south # lsdev -C -c adapter | grep scsi
    scsi0   Available 11-08    Wide/Ultra-2 SCSI I/O Controller
    scsi1   Available 11-09    Wide/Ultra-2 SCSI I/O Controller
  2. Verify the SCSI ID of each adapter:

    north # lsattr -E -l scsi0 -a id
    id 7 Adapter card SCSI ID True
    north # lsattr -E -l scsi1 -a id
    id 7 Adapter card SCSI ID True
    south # lsattr -E -l scsi0 -a id
    id 7 Adapter card SCSI ID True
    south # lsattr -E -l scsi1 -a id
    id 7 Adapter card SCSI ID True
  3. If necessary, change the SCSI identifier on each system so that it is unique:

    south # chdev -P -l scsi0 -a id=5
    scsi0 changed
    south # chdev -P -l scsi1 -a id=5
    scsi1 changed
  4. Shut down all systems in the cluster.

  5. Cable the shared storage as illustrated in Figure: Cabling the shared storage.

  6. Restart each system. After all systems have booted, use the lspv command to verify that each system can see all shared devices needed by the application.

To set up shared storage on HP-UX

  1. Shut down the systems in the cluster.

  2. Install the required SCSI host bus adapters and set up the external shared SCSI storage devices.

  3. Cable the external shared storage devices. With cables connected to shared storage between two systems, you must terminate the two ends of the SCSI bus on the systems as shown in the Figure: Cabling the shared storage.

    For more than two systems, disable SCSI termination on the systems that are not positioned at the ends of the SCSI chain.

To set up shared storage on Linux

  1. Connect the disk to the first cluster system.

  2. Power on the disk.

  3. Connect a terminator to the other port of the disk.

  4. Boot the system. The disk is detected while the system boots.

  5. Press CTRL+A to bring up the SCSI BIOS settings for that disk.

    Set the following:

    • Set Host adapter SCSI ID = 7, or to an appropriate value for your configuration.

    • Set Host Adapter BIOS in Advanced Configuration Options to Disabled.

  6. Format the shared disk and create required partitions on it.

    Perform the following:

    • Identify your shared disk name. If you have two internal SCSI hard disks, your shared disk is /dev/sdc.

      Identify whether the shared disk is sdc, sdb, and so on.

    • Type the following command:

      # fdisk /dev/shareddiskname

      For example, if your shared disk is sdc, type:

      # fdisk /dev/sdc
    • Create disk groups and volumes using Volume Manager utilities.

    • To apply a file system on the volumes, type:

      # mkfs -t fs-type /dev/vx/dsk/disk-group/volume

      For example, enter the following command:

      # mkfs -t vxfs /dev/vx/dsk/dg/vol01

      Where the name of the disk group is dg, the name of the volume is vol01, and the file system type is vxfs.

  7. Power off the disk.

  8. Remove the terminator from the disk and connect the disk to the other cluster system.

  9. Power on the disk.

  10. Boot the second system. The system can now detect the disk.

  11. Press Ctrl+A to bring up the SCSI BIOS settings for the disk.

    Set the following:

    • Set Host adapter SCSI ID = 6, or to an appropriate value for your configuration. Note that the SCSI ID should be different from the one configured on the first cluster system.

    • Set Host Adapter BIOS in Advanced Configuration Options to Disabled.

  12. Verify that you can view the shared disk using the fdisk command.

For Solaris:

When SCSI devices are used for shared storage, the SCSI address or SCSI initiator ID of each node must be unique. Since each node typically has the default SCSI address of "7," the addresses of one or more nodes must be changed to avoid a conflict. In the following example, two nodes share SCSI devices. The SCSI address of one node is changed to "5" by using nvedit commands to edit the nvramrc script.

If you have more than two systems that share the SCSI bus, do the following:

  • Use the same procedure to set up shared storage.

  • Make sure to meet the following requirements:

    • The storage devices have power before any of the systems

    • Only one node runs at one time until each node's address is set to a unique value

To set up shared storage on Solaris

  1. Install the required SCSI host adapters on each node that connects to the storage, and make cable connections to the storage.

    Refer to the documentation that is shipped with the host adapters, the storage, and the systems.

  2. With both nodes powered off, power on the storage devices.

  3. Power on one system, but do not allow it to boot. If necessary, halt the system so that you can use the ok prompt.

    Note that only one system must run at a time to avoid address conflicts.

  4. Find the paths to the host adapters:

    {0} ok show-disks
    ...b) /sbus@6,0/QLGC,isp@2,10000/sd

    The example output shows the path to one host adapter. You must include the path information without the "/sd" directory, in the nvramrc script. The path information varies from system to system.

  5. Edit the nvramrc script on to change the scsi-initiator-id to 5. (The Solaris OpenBoot 3.x Command Reference Manual contains a full list of nvedit commands and keystrokes.) For example:

    {0} ok nvedit
    				

    As you edit the script, note the following points:

    • Each line is numbered, 0:, 1:, 2:, and so on, as you enter the nvedit commands.

    • On the line where the scsi-initiator-id is set, insert exactly one space after the first quotation mark and before scsi-initiator-id.

    In this example, edit the nvramrc script as follows:

    0: probe-all
    1: cd /sbus@6,0/QLGC,isp@2,10000
    2: 5 " scsi-initiator-id" integer-property
    3: device-end
    4: install-console
    5: banner
    6: <CTRL-C>
  6. Store the changes you make to the nvramrc script. The changes you make are temporary until you store them.

    {0} ok nvstore

    If you are not sure of the changes you made, you can re-edit the script without risk before you store it. You can display the contents of the nvramrc script by entering:

    {0} ok printenv nvramrc

    You can re-edit the file to make corrections:

    {0} ok nvedit

    Or, discard the changes if necessary by entering:

    {0} ok nvquit
  7. Instruct the OpenBoot PROM Monitor to use the nvramrc script on the node.

    {0} ok setenv use-nvramrc? true
    				
  8. Reboot the node. If necessary, halt the system so that you can use the ok prompt.

  9. Verify that the scsi-initiator-id has changed. Go to the ok prompt. Use the output of the show-disks command to find the paths for the host adapters. Then, display the properties for the paths. For example:

    {0} ok show-disks
    ...b) /sbus@6,0/QLGC,isp@2,10000/sd
    {0} ok cd /sbus@6,0/QLGC,isp@2,10000
    {0} ok .properties
    scsi-initiator-id     00000005

    Permit the system to continue booting.

  10. Boot the second node. If necessary, halt the system to use the ok prompt. Verify that the scsi-initiator-id is 7. Use the output of the show-disks command to find the paths for the host adapters. Then, display the properties for that paths. For example:

    {0} ok show-disks
    ...b) /sbus@6,0/QLGC,isp@2,10000/sd 
    {0} ok cd /sbus@6,0/QLGC,isp@2,10000
    {0} ok .properties
    scsi-initiator-id      00000007

    Permit the system to continue booting.

See Setting up shared storage.

See Setting up shared storage: Fibre Channel.


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