There are 3 methods for enabling SCSI-3 support from an SFW perspective:

1. VEA GUI (Only available in SFW 5.1 or higher)

Through VEA which allows SFW to send native SCSI-3 commands that will no longer need translation by the DSM. This is configured in VEA > Control Panel > System Settings > 'SCSI Support' tab. And this updates the following registry key:

 

on 32-bit systems:

HKEY_LOCAL_MACHINE\SOFTWARE\Veritas\VxSvc\CurrentVersion\VolumeManager
"SupportSCSI3"=dword:00000001

 

on 64-bit systems:

NOTE
- This is a new feature in 5.1 as previous SFW versions always sent SCSI-2 commands and translation to SCSI-3 was necessary at the DSM level (Multipathing).

- If multiple array models are connected to a server, but not all support SCSI-3, then setting SCSI-3 in VEA is not recommended as SCSI-3 commands sent to the unsupported array(s) would fail. In this case, SCSI-3 support would need to be done at the DSM level (see #2 Registry Key method below).

2. Registry Key

By importing the SCSI3 reg key provided with DSM installations which adds a registry key to the dsm under hklm\system\ccs\services\parameter

Example:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vemcsymm\Parameters]
"SupportSCSI3"=dword:00000001

There is also a 'vxdmpadm setdsmscsi3' command which would be used to perform the same task as manually importing the registry key.

NOTE
- If there are 2 or more of the same arrays, but only wish to use SCSI-3 reservations on some of the arrays and not all, even setting at the DSM level would not work since these arrays are all located under the same DSM (since they are the same array type). In this case, SCSI-3 support would need to be done at the Array level (see #3 below).

3. VXDMPADM command line

By issuing the 'vxdmpadm setarrayscsi3' from a command prompt also updates the DSM, but in a different location as this configuration states that there is 1 or more arrays under the DSM that are configured for SCSI-3 support, but not necessarily all of them.