The types of HBA that are installed on one host can be mixed. However, the HBAs connected to an HDLM-managed device must all be of the same type. Also make sure that the HBA driver versions are the same. If the types or versions of HBAs connected to the devices for the HDLM-managed SCSI disks vary, you cannot switch the path when an error occurs.
You must not change the vendor ID and product ID of the storage system.
If you change these IDs, HDLM cannot recognize the storage system.
Make sure that you start the storage system before starting the host.
When a device is added to a PCI bus, and the IRQ is shared with the HBA and other devices, a problem might occur. When adding a device, make sure that the IRQ is not shared with other devices.
Note the following in an environment where a host is connected to a storage system by using a Fibre Channel switch.
If the host starts while the path between the Fibre Channel switch and the storage system is disconnected, the target ID of the path might be changed after the host restarts. At that time, the disconnected path might not be recoverable while the host is running. Also, when you execute the HDLM command to display the path status, the target ID of the path before the change might be displayed or the disconnected path might not be displayed.
In either case, change the disconnected path so that the configuration is the same as that used when that path operated normally. Physically restore the disconnected path in the same configuration where it used to operate normally. If the HDLM device name has been changed, reconfigure the higher-level program.
If the zone setting for the Fibre Channel switch has changed, the target ID of the path might have also changed. When you execute the HDLM command to display the path status, the target ID of the path before the change might be displayed. In addition, the HDLM device name might be changed after the host is restarted. Check the HDLM device name after the host is restarted. If the HDLM device name has been changed, reconfigure the higher-level program.
However, you can avoid the above situations by setting a permanent target ID for each LU with the HBA driver persistent binding functionality. For details on whether the persistent binding functionality is supported for your HBA driver and the setting method, see the manual provided with the HBA driver.