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3 Replies Last post: May 12, 2009 1:21 AM by wila

Mapping scsi passthru to physical sata disk on 2.0.1

May 9, 2009 10:04 AM

Click to view xyz222's profile Lurker xyz222 2 posts since
May 9, 2009

System is CentOS 5.3 64 bit running on a quad core AMD phenom with 8gb of ram. There are 4 1TB hitachi sata disks installed in the system, visible as /dev/sda sdb sdc and sdd. sda and sdb are beaing used as a raid-1 pair for the Centos Host install and for .vmdk files.

I want to map either /dev/sdc or /dev/sdd to a vm through the scsi passthrough adapter. Scsi passthrough lists available devices as /dev/sg0|1|2|3. Assuming that /dev/sg2 maps to /dev/sdc and /dev/sg3 maps to /dev/sdd if I try to specify either of these sg(2|3) devices for the scsi passthrough, a guest OS installation within the VM does not see any disk associated with the VM.

Interestingly, when I specifiy either /dev/sg0 or /dev/sg1 as my scsi passthrough device, the VM begins to boot my Host installation of CentOS5.3 which I quickly stop to ensure no corruption of my Host OS. So teh scsi passthru seems to work fopr an already installed OS disk.

Just downloaded and installed vmware-server 2.0.1.

What the heck happened to the old RDM capability within vmware-server 1.x?

TIA


Re: Mapping scsi passthru to physical sata disk on 2.0.1 May 11, 2009 1:41 PM
Click to view wila's profile Virtuoso wila 3,207 posts since
Jun 27, 2006
xyz222 wrote:
I'm not sure if you can do what you want to try here. One thing is for sure, it is not going to be supported.
The virtual scsi passthrough device is only meant to be used for SCSI tape devices, trying to use it for anything else can have unpredictable results.
Interestingly, when I specifiy either /dev/sg0 or /dev/sg1 as my scsi passthrough device, the VM begins to boot my Host installation of CentOS5.3 which I quickly stop to ensure no corruption of my Host OS. So teh scsi passthru seems to work fopr an already installed OS disk.
Eeks
What the heck happened to the old RDM capability within vmware-server 1.x?
I think you guessed it already, but it has been removed.


--
Wil
_____________________________________________________
Visit the VMware developers wiki at http://www.vi-toolkit.com
Re: Mapping scsi passthru to physical sata disk on 2.0.1 May 11, 2009 3:16 PM
in response to: wila
Click to view xyz222's profile Lurker xyz222 2 posts since
May 9, 2009
Maybe a better question is 'Why was RDM functionality removed in vmware-server 2.x?'
Re: Mapping scsi passthru to physical sata disk on 2.0.1 May 12, 2009 1:21 AM
in response to: xyz222
Click to view wila's profile Virtuoso wila 3,207 posts since
Jun 27, 2006
I'm afraid that only VMware can answer that question and I doubt they will answer it here.

My guess is that it is a premium feature they only want to support for paying customers?
RDM support is still available in VMware workstation.

I'm aware it is not in the user interface anymore, but that doesn't say it is not still working that way anymore.
Unfortunately i cannot test it here.


--
Wil
_____________________________________________________
Visit the VMware developers wiki at http://www.vi-toolkit.com

edit: Another guess is that the Windows product under Vista doesn't allow RDM mappings anymore as the OS doesn't give you direct access to the disk. VMware usually tries to keep their products the same over ALL operating systems and by removing the feature it is the same....
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