The info below (thanks to Chaffie McKenna) may be what you are looking for. Also, please check the info at: http://wikid.netapp.com/w/ONTAP_Blocks/Lun_Types
Selecting the correct LUN Protocol Type
When creating the NetApp LUN using the FilerView or CLI, the parameter “LUN Type” plays a very critical role. This parameter determines the on-disk layout of the LUN. It is important to specify the correct LUN type to make sure that the LUN is properly aligned with the file system on it. The underlying reason is that optimal performance with the storage system requires that I/O be aligned to a 4096-byte boundary. Unaligned I/O may cause an increase in per operation latency. Unaligned I/O requires the storage system to read from or write to more blocks than necessary to perform logical I/O. This issue is not unique to NetApp storage. Any storage vendor or host platform may exhibit this problem.
The LUN type you specify depends on the OS, OS version, disk type, and Data ONTAP version. If the incorrect LUN type is selected when the LUN is initially provisioned, a new LUN (with the correct LUN type) will need to be created, and the data will need to be transferred from the existing misaligned LUN. For complete information on LUN types for different OS’s, see the Block Access Management Guide for your version of Data ONTAP.
Please review Table 1-3 below to determine the LUN types to use when configuring LUNs for use with Windows Server 2008, for installations with and without the Hyper-V role enabled.
Table 1) LUN Types for use with Data ONTAP 7.3.1 and later
Data ONTAP 7.3.1 or later | Windows Server 2008 Physical Server w/o Hyper-V | Windows Server 2008 Hyper-V Server Physical Disk | Windows Server 2008 Hyper-V Server Pass-Through Disk |
With SnapDrive installed | windows_gpt | hyper_v | LUN type of Child OS |
Without SnapDrive installed | windows_2008 | windows_2008 | LUN type of Child OS |
Table 2) LUN Types for use with Data ONTAP 7.2.5 through 7.3.0
Data ONTAP 7.2.5 through 7.3.0 | Windows Server 2008 Physical Server w/o Hyper-V | Windows Server 2008 Hyper-V Server Physical Disk | Windows Server 2008 Hyper-V Server Pass-Through Disk |
With SnapDrive installed | windows_gpt | windows_gpt | LUN type of Child OS |
Without SnapDrive installed | windows_2008 | windows_2008 | LUN type of Child OS |
Table 3) LUN Types for use with Data ONTAP 7.2.4 and earlier
Data ONTAP 7.2.4 or earlier | Windows Server 2008 Physical Server w/o Hyper-V | Windows Server 2008 Hyper-V Server Physical Disk | Windows Server 2008 Hyper-V Server Pass-Through Disk |
With SnapDrive installed | linux | linux | LUN type of Child OS |
Without SnapDrive installed | linux | linux | LUN type of Child OS |
For Data ONTAP version 7.3 and earlier, the LUN type “windows_2008” is available only through the Data ONTAP CLI. Therefore, the LUNs for Hyper-V parent partition and Windows Server 2008 Child VMs must be created through the LUN setup command on the Data ONTAP CLI.
For LUNs directly mapped to the child OS using the iSCSI software initiator running in the VM, the LUN type of the intended child OS should be selected when creating the LUN. In addition, for LUNs assigned directly to the Child OS via a Pass-through disk configured for the Hyper-V server, the LUN type of the intended child OS should be selected when creating the LUN.
Hope that helps,
Wei