Why set OS Type?

[Joshua Baldock]

Hey,

Quick technical questions. We have an EVA4100 and EVA8000. When creating hosts in commandview I know i need to set the Operating System Type to the correct type for LUNs to be properly presented. I have seen issues if a windows server for instance, is unable to see its luns if the OS Type isn't configured to Windows for the Host in CommandView.

I have also read a lot of post similar to the above, but relating to Vmware and configuring the os type to vmware.

Technically I would like to know why this needs to be set and what happens to the backend when this is selected. As I would have thought that the fibre / scsi protocol should be the same across all hardware / software.

Look forward to your knowledge on this question.

[IBaltay]

Hi,
the EVA host mode is the EVA host/host group
layer/setting for the proper communication of the host OS (multipathing) drivers with the EVA vdisks (BC/CA included, so you definitely need to have the correct host mode settings to have error free host/EVA communication...

[Nguyen Anh Tien]

witch vmware, you must set host type as host type on what you installed vmware SW. virtual host will communicate with this host to translate data type
HTH

[Joshua Baldock]

I still don't understand why HP EVA's have different 'mutlipath driver' communication dependant on the the different host OS? Is there any whitepapers / documentation on this that would explain it better?

Again every other vendor's SAN i have worked with has never used nor needed this option.

[IBaltay]

Hi,
because the different platforms have different multipathing solution e.g.:
Linux device mapper
Solaris MPxIO
AIX MPIO
HP-UX PVlinks, Secure Path, MPIO
Windows MPIO DSM, ... etc.

[Joshua Baldock]

So why is this relevant on the storage side? Shouldn't the OS handle any sort of driver / kernel module that recognizes the storage and the way it communicates to the storage?

And why are EVA's different in this way to other Vendor San's?

[IBaltay]

Hi,
here is one comparison e.g.:

EMC Power Path/ Linux GNU DM multipath:
http://blog.thilelli.net/post/2009/02/09/Comparison:-EMC-PowerPath-vs-GNU/Linux-dm-multipath

So this is not EVA specific,
Also e.g. HP XP, Hitachi, IBM use the host types/host modes:
ftp://service.boulder.ibm.com/software/campus/ds6000gui.pdf

[tore_3]

Different Operatingsystem have different scsi command set.
Historically different vendors did this to protect there HW investment so IBM would not work with HP storage for an example.