Primary and alternative paths
When the device driver configures a logical device with path failover support enabled, the first device that is configured always becomes the primary path. On SCSI attached devices, -P is appended to the location field. On Fibre attached devices, -PRI is appended to the location field of the device.
When a second logical device is configured with path failover support enabled for the same physical device, it configures as an alternative path. On SCSI attached devices, -A is appended to the location field. On Fibre attached devices, -ALT is appended to the location field of the device.
A third logical device is also configured as an alternative path with either -A or -ALT appended, and so on. The device driver supports up to 16 physical paths for a single device.
- Be able to identify the actual number of physical devices that are configured on the system and a specific logical device that is associated with them. Only one logical device is labeled as the primary path for each physical device. However, many (multiple) logical devices can be labeled as an alternative path for the same devices.
- Provide information about which logical devices configured on the system have path failover support enabled.