Configuring Multiple Host Access for a J4500 Array

The example in this section describes an initial multi-host set up with each host owning a separate portion of array storage that is configured using the CAM browser interface. The storage owned by each host is configured for multipath failover. Do the following before you begin:

• If you have already configured operating system multipath software for a host, disable the multipath software until after the CAM access configuration is complete so that CAM will see all array-connected initiators.

• If your server is running the Windows Server 2008 operating system and you have already configured multipathing, remove the J4500 array disk drives from the MPIO-ed Devices list (through Control Panel -> MPIO properties).

To Configure Multiple Host Access for a J4500 Array

1. If not done already, install the full version of CAM (6.4.1 at a minimum) on a server you designate as the primary (first) host.

   The server used to configure access configuration can also be the combination of a network-connected Management station and a single proxy server directly connected to array storage designated as the primary host.

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   Note - For other hosts that will be connected, you must remove CAM proxy agents (if installed) prior to performing the following steps in order to prevent SATA affiliation issues. In addition, no commands that might access the disks should be run from any host other than the chosen primary host. For more information see the “Troubleshooting Access Configuration” section in the Sun StorageTek Common Array Manager Release Notes.

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2. Cable your servers to the arrays in a supported configuration (refer to Multipathing Configuration Guidelines). When multipathing using two initiators, connect one path to array SAS A and one to SAS B. Initiator connections should be at opposite ends of the array SAS fabrics (see Temporary Cascade Configuration).

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   Note - If any re-cabling of an existing host and array setup is required to achieve a supported multi-host cascaded configuration, you must record the initiator SAS address and any desired disk associations from the CAM Access Configuration page before re-cabling. If the initiator moves from one array connector port to another (even in the same SAS fabric) its disk access configuration will need to be re-created.

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   Figure 3-14 Multiple Host Connection to Cascaded J4500 Arrays

   
3. Power on the arrays by reconnecting AC power.
4. After a minute, power on the primary host.
5. Log into CAM on the primary host by opening the browser and entering the following address:

   https://host-name:6789

   Where host-name is the DNS name of the server connected to the array.

6. From the Storage System Summary page, click Register and follow the wizard to register the cascaded arrays using the host name or host IP address of the primary host in the Registration window.

   All attached arrays should be found. If they are not, perform a host reboot (i.e. Full reboot reconfigure on Solaris) and attempt the registration again.

7. In the left navigation pane, expand the tree for the connected server host and click Access Configuration for the first SAS Domain which is represented by the domain's SAS address number.

   The Access Configuration Summary page displays. See Example Access Configuration Summary Page.

   
   

   Figure 3-15 Example Access Configuration Summary Page

   
8. Click Configure.

   The Configure Access Between Initiators and Disks page displays. See Example Access Configuration Between Initiator and Disks Page.

   At this time, all arrays, domains, and initiators from all attached hosts should be seen within the corresponding Access Configuration Pages.

   If any initiators from any attached hosts are not seen, verify that the OS multipathing software is disabled on those hosts. In addition, a reboot might be necessary to force an attached host to register their initiators with the storage arrays.

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   Note - In the Access Configuration page, the initiator(s) from the additional host(s) should be visible; however, they may only be represented as unique SAS addresses (no host names) since the proxy has not been discovered yet.

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   Figure 3-16 Example Access Configuration Between Initiator and Disks Page

   
9. At the Configure Access Between Initiators and Disks page, configure initiator-to-disk relationships for an initiator as follows:
   1. Select an initiator and then select the disks to be given access to that initiator.

      • If the initiator selected is from a host whose cable did not need to be moved from one array port to another in order to conform to a supported array cascade configuration, you can implement an existing access configuration for it. Any host connections that were moved from their original array port connection to a different array port must have access configuration manually recreated for that initiator.

      • If multipathing is planned, drives may be shared by the initiators of a single host. The initiators must be attached to separate SAS domains to ensure a separate failover path. Disk drives in the array should never be shared by more than one host whether multipathing or not.

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        Note - The J4500 array is not supported in a clustering configuration.

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   2. Click Add/Modify to store the configuration to the Initiator Centric Access List.
   3. Verify the Access Configuration state is set to “Enable”.
   4. Click Save.
   5. Repeat Steps A through D for each initiator.

      All initiators should be configured at this time (i.e., initiator #1 might have all odd numbered disks and initiator #2 might have all even numbered disks). This includes the initiators of other attached hosts.

10. Repeat Steps 7 through 9 to configure other initiator-to-disk relationships for the other SAS domains found under the entry for the primary host.

    If multiple initiators are seen, access configuration should also be performed at this time. This includes the initiators of other attached hosts.

11. When done, power cycle the attached hosts. This will perform a full re-scan of the attached storage.
12. After all hosts are powered up, do the following:

    • Install and discover the CAM proxy agents on any additional hosts other than the primary CAM host. For installation information, see the Sun StorageTek Common Array Manager User Guide for your version of CAM.

    • Verify the appropriate Access Configuration is now active (for example, on an array-attached host running Solaris, use the format utility to confirm that only disks configured for the initiators of that host are now available).

    • Verify operating system multipathing software is installed/enabled and configured for each server. Verify that the disk drives show both paths to the operating system (see Chapter 4, SAS Multipathing).

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      Note - If your server is running the Windows Server 2008 operating system, and you had previously configured it for multipathing, add back the J4500 array disk drives to the MPIO-ed Devices list (through Control Panel -> MPIO properties).

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