Host modes for host groups

The following table lists the host modes that are available for use on your storage system. Carefully review and determine which host modes you will need to use when configuring your system and observe the cautions concerning using certain host modes. Host modes and host mode options must be set on the port before the host is connected. If you change host modes or host mode options after the host is connected, the host (server) will not recognize it.

Host mode

When to select this mode

00 Standard

When registering Red Hat Linux server hosts or IRIX server hosts in the host group1

01 (Deprecated) VMware

When registering VMware server hosts in the host group1, 2

03 HP

When registering HP-UX server hosts in the host group

05 OpenVMS

When registering OpenVMS server hosts in the host group

07 Tru64

When registering Tru64 server hosts in the host group

09 Solaris

When registering Solaris server hosts in the host group

0A NetWare

When registering NetWare server hosts in the host group

0C (Deprecated) Windows

When registering Windows server hosts in the host group2, 3

0F AIX

When registering AIX server hosts in the host group4

21 VMware Extension

When registering VMware server hosts in the host group. If the virtual host on VMware recognizes LUs by the Raw Device Mapping (RDM) method, set the host mode related to OS of the virtual host.1

Example: If a LUN/LDEV is formatted as VMFS (where virtual machines and their VMDK’s usually reside), it should be set with HMO 21. However, if a LUN/LDEV is formatted as a specific file system format (for example, NTFS) and has application requirements to be presented directly to a virtual machine as an RDM, it should be set to the HMO specific to that OS/filesystem (e.g., such as HMO 2C for Windows).

A common example of VM’s with this mix would be:

C: drive – OS VMDK on VMFS

D: drive – RDM for application data

In this example, 2 different Host Groups should be created for a single host with different HMO and LUN’s assigned.

2C Windows Extension

When registering Windows server hosts in the host group.1

Notes:

  1. You can add the following types of server hosts to one host group:
    • VMware server host, which includes the case that the (Linux based OS or Windows) virtual host recognizes LUs by RDM (Raw Device Mapping), and also includes the case that the Linux based OS or Windows virtual hosts are being operated on VMFS of VMware.
    • Linux based OS (such as Red Hat Linux) server host.
    • Windows server host

    If you want to add these sever hosts to one host groups, you must set following host mode and host mode options for the host group.

    • Host mode: 21 VMware Extension
    • Host mode options: 2, 22, 25, 40, 54, 63, 68, and 110

    Restrictions for the VMWare server host added to the host group. If the OS of the virtual host on VMware is Windows, the following functions that are supported by Windows cannot be used.

    • Thin Provisioning
    • Offload Data Transfer (ODX)

    Restrictions for the Windows server host which added to the host group In this environment, the thin provisioning function which is supported by the Windows server host cannot be used. Therefore, you must not set the host mode option 73. If you set the host mode option 73, the thin provisioning function for the Linux server host does not work. If you want to use the thin provisioning function supported by the Windows server host, add only windows server host to the host group to which the following options are set.

    • Host mode: 2C Windows Extension
    • Host mode options: 73

  2. There are no functional differences between host mode 01 and 21. When you first connect a host, it is recommended that you set host mode 21.
  3. There are no functional differences between host mode 0C and 2C. When you first connect a host, it is recommended that you set host mode 2C.
  4. When host mode 0F for AIX is set, NACA is enabled automatically. Take the following steps to ensure that the host responds correctly to a port with host mode 0F enabled:
    1. Shut down the host to be connected to the port.
    2. Set the host mode on the port to 0F.
    3. Connect the cables from the host to the port.
    4. Boot the host.
    CautionIf the host mode of a port is changed to 0F and the host already recognized the Inquiry response for an LDEV on the port with host mode other than 0F, the host might experience loss of device (LDEV or LUN) access. The host must be rebooted after host mode 0F is set to recognize the change in the response of the standard inquiry.

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