How do I know which host operating system type is correct?

The Host Operating System Type field contains the operating system of the host. You can select the recommended host type from the drop-down list or allow the Host Context Agent (HCA) to configure the host and appropriate host operating system type.

Host Operating System type Operating System (OS) and multipath driver
AIX MPIO The Advanced Interactive Executive (AIX) OS and the native MPIO driver
AVT_4M Silicon Graphics, Inc. (SGI) proprietary multipath driver; refer to the SGI installation documentation for more information
Factory Default This is reserved for the initial startup of the storage array and should be changed to match the host operating system and multipath driver being used for the particular host
HP-UX The HP-UX OS with native multipath driver
Linux (ATTO) The Linux OS and the ATTO Technology, Inc. driver (must use ATTO FC HBAs)
Linux (DM-MP) The Linux OS and the native DM-MP driver
Linux (Pathmanager) The Linux OS and the SGI proprietary multipath driver; refer to the SGI installation documentation for more information
Mac OS The Mac OS and the ATTO Technology, Inc. driver
ONTAP FlexArray
Solaris (version 11 or later) The Solaris 11 or later OS and the native MPxIO driver
Solaris (version 10 or earlier) The Solaris 10 or earlier OS and the native MPxIO driver
SVC IBM SAN Volume Controller
VMware The ESXi OS
Windows or Windows Clustered The Windows Server OS and Windows MPIO with a DSM driver
Windows (ATTO) The Windows OS and the ATTO Technology, Inc. driver
After the HCA is installed and the storage is attached to the host, the HCA sends the host topology to the storage controllers through the I/O path. Based on the host topology, the storage controllers automatically define the host and the associated host ports, and then set the host type.
Note:

If the HCA does not select the recommended host type, you must manually set the host type in System Manager.