Setting Up Shared Storage

The following sections describe setting up SCSI and Fibre Channel devices that are shared among the cluster systems.

If you intend to use VCS I/O fencing, the disks you use must support SCSI-III persistent group reservations. In addition, you must configure a coordinator disk group. See Setting Up I/O Fencing for information on verifying SCSI-III persistent group reservation support. See also the VERITAS Cluster Server User's Guide for a description of I/O fencing.

Setting Up Shared Storage: SCSI

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 below:

   

   Click the thumbnail above to view full-sized image.

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

Checking and Changing SCSI Initiator IDs

Because the SCSI Initiator IDs for the host bus adapters (HBAs) on each of the systems accessing shared storage must be unique, you may have to change the HBA SCSI ID on one or more systems if they are the same. Typically, the host bust adapters (HBAs) for the SCSI devices are shipped with a default SCSI ID of 7. Use the following procedure to check SCSI IDs and change them if necessary.

1. Turn on the power of the first system. During the boot process, the system delays for ten seconds, giving you the opportunity to stop the boot process and enter the boot menu:
     To discontinue, press any key within 10 seconds.

   Press any key. The boot process discontinues.

   
     Boot terminated.
2. When you see the boot Main Menu, display the Information Menu by entering:
     Main Menu: enter command or menu > in
3. From the Information Menu, enter "io" at the prompt for I/O interface information:
     Information Menu: Enter command > io

   The output shows information about the I/O interfaces and resembles:

   
                      Path      Bus     Slot    Vendor     Device
     Description     (dec)       #       #       Id          Id
     -----------     ----       ---    -----    ------     ------
     .
     .
     SCSI bus cntlr  0/3/0/0    24      10      0x1000      0xf
     .
4. Return to the Main Menu:
     Information Menu: Enter command > main
5. Go the Service Menu:
     Main Menu: enter command or menu > ser
6. Display the host bus adapter's SCSI ID:
     Service Menu: enter command or menu > scsi

   The output displays information about the SCSI devices:

   
     Path (dec)       Initiator ID    SCSI Rate     Auto Term
     --------------   ------------    ---------     ---------
     0/3/0/0          7               Fast          Unknown

   The output in this example shows the SCSI ID is 7, the preset default for the HBA as shipped.

   1. If you choose, you can leave the ID set at 7 and return to the Main Menu:
   
       Service Menu: enter command or menu > main
   2. You can change the SCSI ID for the HBA. For example, to change the SCSI ID from 7 to 6, you would enter:
   
       Service Menu: Enter command > SCSI init 0/3/0/0 6 FAST
   3. To verity the change, enter "SCSI" at the prompt:
   
       Service Menu: Enter command > SCSI
   
       Path (dec)       Initiator ID    SCSI Rate     Auto Term
        --------------   ------------    ---------     ---------
        0/3/0/0          6               Fast          Unknown
7. Return to the Main Menu:
     Service Menu: enter command or menu > main
8. At the Main Menu, enter the command to boot the system. Answer "n" when you are prompted to interact with IPL:
     Menu: Enter command or menu > boot 
     Interact with IPL (Y, N, or Cancel)?> n
     
     Booting... 

Setting Up Shared Storage: Fibre Channel

1. Shut down the cluster systems that are to share the devices.
2. Install the required Fibre Channel host bus adapters on each system.
3. Cable the shared devices.
4. Reboot each system.
5. Verify that each system can see all shared devices using the command:
     ioscan -fnC disk

   Where "disk" is the class of devices to be shared. For example, from northhp:

   
     northhp# ioscan -fnC disk
     Class  I  H/W Path     Driver S/W State   H/W Type  Description
     ===============================================================
     .
     .
     disk      4  0/4/0/0.1.16.255.13.4.0  sdisk  CLAIMED     DEVICE
      SEAGATE ST318304 CLAR18
                     /dev/dsk/c4t4d0   /dev/rdsk/c4t4d0
     disk      5  0/4/0/0.1.16.255.13.5.0  sdisk  CLAIMED     DEVICE
      SEAGATE ST318304 CLAR18
                       /dev/dsk/c4t5d0   /dev/rdsk/c4t5d0
     .
     .

   And on south, enter:

   
     south# ioscan -fnC disk
     Class  I  H/W Path     Driver S/W State   H/W Type  Description
     ===============================================================
     .
     .
     disk      4  0/4/0/0.1.16.255.13.4.0  sdisk  CLAIMED     DEVICE
      SEAGATE ST318304 CLAR18
                     /dev/dsk/c4t4d0   /dev/rdsk/c4t4d0
     disk      5  0/4/0/0.1.16.255.13.5.0  sdisk  CLAIMED     DEVICE
      SEAGATE ST318304 CLAR18
                       /dev/dsk/c4t5d0   /dev/rdsk/c4t5d0
     .
     .