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Hitachi Vantara Knowledge

Host modes and host mode options for host groups and iSCSI targets

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 group

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.

Host mode options

The following table lists the host mode options (HMOs) that are available to use for configuring hosts on your storage system.

No.

Host mode option

When to select this option

2

VERITAS Database Edition/ Advanced Cluster

Oracle Solaris Cluster (Sun Cluster)

When VERITAS Database Edition/Advanced Cluster for Oracle Real Application Clusters or VERITAS Cluster Server 4.0 or later (I/O fencing function) is used.

When Oracle Solaris Cluster (Sun Cluster) is used.

6

TPRLO

When all of the following conditions are satisfied:

  • The host mode 0C (Deprecated) Windows or 2C Windows Extension is used.
  • The Emulex host bus adapter is used.
  • The mini-port driver is used.
  • TPRLO=2 is specified for the mini-port driver parameter of the host bus adapter.

7

Automatic recognition function of LUN

When all of the following conditions are satisfied:

  • The host mode 00 Standard or 09 Solaris is used.
  • SUN StorEdge SAN Foundation Software Version 4.2 or later is used.
  • You want to automate recognition of increase and decrease of devices when genuine SUN HBA is connected.

12

No display for ghost LUN

When all of the following conditions are satisfied:

  • The host mode 03 HP is used.
  • You want to suppress creation of device files for devices to which paths are not defined.

13

SIM report at link failure1

When you want to be informed by SIM (service information message) that the number of link failures detected between ports exceeds the threshold.

14

HP TruCluster with TrueCopy function

When all of the following conditions are satisfied:

  • The host mode 07 Tru64 is used.
  • You want to use TruCluster to set a cluster to each of primary volume and secondary volume for TrueCopy or Universal Replicator.

15

HACMP/PowerHA®

When all of the following conditions are satisfied:

  • The host mode 0F AIX is used.
  • HACMP* or PowerHA® is used.

* HACMP 4.5 version 4.5.0.13 or later, HACMP 5.1 version 5.1.0.4 or later, or HACMP 5.2 or later.

22

Veritas Cluster Server

Oracle Solaris Cluster (Sun Cluster)

When Veritas Cluster Server is used.

When Oracle Solaris Cluster (Sun Cluster) is used.

25

Support SPC-3 behavior on Persistent Reservation

When one of the following conditions are satisfied:

  • Using Windows Server Failover Clustering (WSFC)
  • Using Microsoft Failover Cluster (MSFC)
  • Using Symantec Cluster Server, also known as Veritas Cluster Server (VCS)
  • Using a configuration other than above with the PERSISTENT RESERVE OUT (Service Action=REGISTER AND IGNORE EXISTING KEY) command, change the status response from Reservation-Conflict to Good-Status when there is not a registered key to be deleted

33

Set/Report Device Identifier enable

When all of the following conditions are satisfied:

  • Host mode 03 HP or 05 OpenVMS1 is used.
  • You want to enable commands to assign a nickname of the device.
  • You want to set UUID to identify a logical volume from the host.

39

Change the nexus specified in the SCSI Target Reset

When you want to control the following ranges per host group when receiving Target Reset:

  • Range of job resetting.
  • Range of UAs (Unit Attentions) defined.

40

V-VOL expansion

When all of the following conditions are satisfied:

  • The host mode 0C (Depreated) Windows or 2C Windows Extension is used.
  • You want to automate recognition of the DP-VOL capacity after increasing the DP-VOL capacity.

43

Queue Full Response

When the command queue is full in your storage system connecting with the HP-UX host, and if you want to respond Queue Full, instead of Busy, from the storage system to the host.

51

Round Trip Set Up Option3

If you want to adjust the response time of the host I/O, for example when the distance between MCU and RCU of the TrueCopy (or global-active device) pair is long (approximately 100 kilometers) and Point-to-Point topology is used.

54

(VAAI) Support Option for the EXTENDED COPY command

When the VAAI (vStorage API for Array Integration) function of VMware ESX/ESXi 4.1 or later is used.

63

(VAAI) Support Option for vStorage APIs based on T10 standards

When you connect the storage system to VMware ESXi 5.0 or later and use the VAAI function for T10. Use a combination of this host mode option and host mode option 54.

67

Change of the ED_TOV value

When using the FCAL topology and direct connection in the OPEN Fibre Channel Port configuration.

68

Support Page Reclamation for Linux

When using the Page Reclamation function from the environment which is being connected to the Linux host.

71

Change the Unit Attention for Blocked Pool-VOLs

When you want to change the unit attention (UA) from NOT READY to MEDIUM ERROR during the pool-VOLs blockade.

73

Support Option for WS2012

When using following functions provided by Windows Server 2012 (WS2012) or later from the environment which is being connected to the WS2012 or later.

  • Dynamic Provisioning function
  • Offload Data Transfer (ODX) function

78

The non-preferred path option

When all of following conditions are satisfied:

  • Global-active device is used in the configuration with the data centers (Metro configuration).
  • Hitachi Dynamic Link Manager is used as the alternative path software.
  • The host group is on the non-optimized path of Hitachi Dynamic Link Manager.
  • The performance deterioration of I/O responses can be avoided without I/O using the non-optimized path of Hitachi Dynamic Link Manager.

80

Multi Text OFF

By using the iSCSI interface, if the storage system connects with the host of which OS is not supported of the Multi Text function. For instance, connecting the storage system and the host of RHEL5.0 which does not support the Multi Text-function.

81

NOP-In Suppress Mode

In the environment by iSCSI connection, the delay replying of the Delayed Acknowledgment function which is located on the upper layer is restrained by sending NOP-IN of executing of sense commands such as Inquiry, Test unit ready, or Mode sense. However, select this option when connecting the storage system and the host which is not necessary of the NOP-IN sending. However, when connecting the storage system and the host which does not need of the NOP-IN sending, select this option.

For instance:

  • When connecting the storage system and the Open Enterprise Server of Novell Co., Ltd.
  • When connecting the storage system and winBoot/i of emBoot Co., Ltd..

82

Discovery CHAP Mode

Select this option when the CHAP authentication is performed at the time of the discovery login In the iSCSI connection environment.

For instance: When the CHAP authentication is performed at the time of the discovery login in the iSCSI environment of the VMware host and storage system

83

Report iSCSI Full Portal List Mode

When configuring alternate paths in the environment of connecting the VMware host and storage system: If waiting of replying of the target information from the host option mode 83 enabled port other than ports of discovery login, select this host mode option.

Apply this host mode option when all of the following conditions are met:

  • Configuring alternate paths in the environment of connecting the VMware host and storage system.
  • Waiting for replying of the target information from the ports other than ports of discovery login.

88

Nondisruptive migration with HP-UX hosts

When converging multiple host-target ports used in the migration source storage system on the migration target storage system, and enable LUN path definition from a host group belonging to a virtual storage machine to an LDEV defined in a different virtual storage machine.

  • ON: LUN path definition is enabled.
  • OFF: LUN path definition is disabled.

Note:

  1. Apply this host mode option when all the following conditions are met:

    - You are using the nondisruptive migration function to migrate volumes in multiple old storage models that use the same server.

    - You need to reduce the number of Target ports used on the migration target storage system.

    - The host is an HP-UX server.

  2. Applying this option to a server other than HP-UX can cause the following:

    - Path addition from the server to the migration target storage system might fail.

    - Display of devices that the server recognizes might be invalid.

  3. If a LUN path is defined to an LDEV defined in a virtual storage machine different from the one to which the host group belongs, this option cannot be set to OFF.

91

Disable I/O wait for OpenStack Option

When manually creating host groups (for Fibre Channel) or iSCSI targets (for iSCSI) that are used as the I/O data paths for OpenStack.

96

Change the nexus specified in the SCSI Logical Unit Reset

When you want to control the following ranges per host group when receiving LU Reset:

  • Range of job resetting.
  • Range of UAs (Unit Attentions) defined.

102

(GAD) Standard Inquiry Expansion for Hitachi Command Suite

When all of the following conditions are satisfied:

  • The OS of the host is Windows (host mode 0C (Deprecated) Windows or 2C Windows Extension) or AIX (host mode 0F AIX), and the MPIO function is used.
  • Global-active device (GAD) or nondisruptive migration (NDM) is used.
  • Hitachi Device Manager (HDvM) agent is used.

105

Task Set Full response in the event of I/O overload

When all of following conditions are satisfied:

  • The host mode 0C Windows or 2C Windows Extension is used.
  • You want to return Task Set Full response from the storage system to the host when an overload of I/Os occurs on the storage system.

110

ODX support for WS2012

When ODX (Offload Data Transfer) provided by Windows Server 2012 or later is used, in the environment with which the WS2012 or later host connects.

113

iSCSI CHAP Authentication Log4

When the result of the CHAP authentication is output to the audit log (DKC).

114

The automatic asynchronous reclamation on ESXi 6.5 or later

When connecting to VMware ESXi 6.5 or later, and when using the zero data page reclamation function which is performed automatically if files on the VMFS (Virtual Machine File System) are deleted.

Use a combination of this host mode option and host mode option 63.

Notes:

  1. Configure these host mode options only when requested to do so.
  2. Set the UUID when you set host mode option 33 and host mode 05 openvms is used.
  3. Set the host mode option 51 for ports on the remote site of the Hitachi TrueCopy® pair or the global-active device pair.
  4. The setting of this host mode option is effective on a basis of a port. Set this host mode option in the iSCSI target 00 of the port.