Host mode option (HMO) 51, round-trip setup option, should be set only on a host group configured on ports designated for remote replication. When applied to the host group of ports designated for replication, HMO 51 causes a link-down and link-up event. Therefore, apply HMO 51 prior to putting the link in production. Furthermore, all supported operating systems can send traffic through the designated replication link when HMO 51 is enabled on the host group of the designated replication ports. Ensure that HMO 51 is set on the host group of both the source and the target designated replication group.
To keep the configuration simple, set HMO 51 on the default host group of the ports designated for replication and keep LUN security turned off. If you must enable LUN security, then you must create an arbitrary host group on the designated replication port, register the WWPN of the desired remote array replication port to the host group, apply the desired HMOs to this host group, and turn LUN security on. To delete this arbitrary host group, first disable the HMOs on the host group.
| HMO | Function | Host mode | Description |
|---|---|---|---|
| 51 | Round Trip Set Up Option | Any | Use this HMO if you want to adjust the response time of the host I/O, for example when the distance between the primary and secondary storage systems in the TrueCopy or global-active device pair is long (approximately 100 km) and point-to-point topology is used. For further information, see the section below this table. |
HMO 51 details
- When the HMO 51 setting is changed to ON or OFF, a link-down and link-up occur on the target port, and an SSB log of link down is output on RCU (R-DKC).
- This HMO can work only when the microcode supporting this function is installed on both MCU (M-DKC) and RCU (R-DKC).
- This function is only applicable when the DW-F800-4HF32R PCB is used.
- When removing the DW-F800-4HF32R PCB, the operation must be performed after setting HMO 51 to OFF.
- If this option is used, Point to Point setting is necessary.
- If HMO 51 is set to ON while SOM 769 is ON, path creation might fail after automatic port switching.
- Make sure to set HMO 51 from OFF to ON or from ON to OFF after the pair is suspended or when the load is low.
- The RCU Target, which is connected with the MCU where this option is set to ON, cannot be used for Universal Replicator.
- Path attribute change (Initiator Port - RCU-Target Port, RCU-Target Port - Initiator Port) accompanied with Hyperswap is enabled after setting HMO 51 to ON. If HMO 51 is already set to ON on both paths, HMO 51 continues to be applied on the paths even after execution of Hyperswap.
- This function is available in the following configuration:
- Supported version: DW-F800-4HF32R: All versions
- Supported configuration: Point to Point setting with HMO 49 and HMO 50 set to ON while the path distance between MCU and RCU meets requirements of each program product. In the case of DW-F800-4HF32R, setting HMO 49 and HMO 50 is not necessary as it does not support the options.