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SPARC T8 Series Servers Administration Guide

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Updated: September 2017
 
 

WWN Syntax

Oracle Solaris uses the WWN (World Wide Name) syntax in place of the locally unique tn (target ID) field in logical device names. This change affects how device names can be mapped to specific SCSI devices. The following points are key to understanding the impact of this change:

  • Before the change to WWN nomenclature, Oracle Solaris identified the default boot device as c0t0d0.

  • With the change, the device identifier for the default boot device is now referred to as c0tWWNd0, where WWN is a hexadecimal value that is unique to this device throughout the world.

  • This WWN value is assigned by the manufacturer of the device and, therefore, has a random relationship to the server's device tree structure.

Because WWN values do not conform to the traditional logical device name structure, you cannot directly identify a target device from its cntWWNdn value. Instead, you can use one of the following alternative methods to map WWN-based device names to physical devices.

  • When the OS is not running, you can analyze the output of the OpenBoot command probe-scsi-all.

    For example, you would analyze probe-scsi-all output when you want to identify a boot device.

  • When the OS is running, you can analyze the output of the command prtconf -v.

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