SAN Vdisk Mapping in OpenVMS Clusters

[Robert Jacobs]

I am just going to foward a requeset from a co-worker and hope for the best!



Thank you



Questions:

1) What is the scope of the uniqueness of the UDID? Does it need to be stored per vdisk or per host-scsi-vdisk mapping? What I am getting at here is if you have an OpenVMS cluster, could different hosts have different UDIDs for the same vdisk, or would the UDID be tied to the vdisk so anything querying it would get the same UDID (regardless of host)?


2) What is the specification of the vendor specific command required in order to send the UDID to the host when requested. Please provide the format of the CDB, any parameter data and the response frame, plus anything else that might be useful (such as values of parameters and what any specific flags do).

[Andy Bustamante]

1. The wwid needs to be stored for the boot disk and if enabled the disk the dumpfile is written to. Within a fibre configuration, each disk would have a unique identifier that is the same on each system. OpenVMS will detect other disks when booted.

2. At the console you use the wwidmgr utility to configure the UDID. This manual is on the firmware CD in pdf format. You can download the manual from ftp://ftp.digital.com/pub/Digital/Alpha/firmware/readmes/v7.0/doc/wwidmgr_v13.pdf

There are some slight differences in older Alphaservers (4100).

[Robert Jacobs]

Hi

When dealing with a Virtualization product like and EVA I am not sure how the cluster sees each vdisk from a UDID stand point?

Any details would be great in regards to how each member of the Cluster needs to see the VDISK specifics etc...

Thanks you

[Bill Hall · Accepted solution]

Robert,

The UDID will be the unit number of the drive. On a VMS system all fibre channel disk devices are assigned an allocation class 1, device class DG, controller A, and unit number (UDID), i.e. $1$DGA:. All fibre channel attached tape devies are prefixed by $2$MGA.

ALL members of VMS cluster must reference a shared device using the SAME identifier.

[Robert Brooks_1]

Robert Jacobs wrote . . .

2) What is the specification of the vendor specific command required in order to send the UDID to the host when requested. Please provide the format of the CDB, any parameter data and the response frame, plus anything else that might be useful (such as values of parameters and what any specific flags do).


Given the above, it's apparent that your colleague is interested in more than just system-management-level knowledge. What, exactly, is he trying to do? How does he plan to send the CDB -- using the IO$_DIAGNOSE interface, perhaps?



-- Rob

[Uwe Zessin]

I'd say this is a vendor who offers a virtualization box (like Datacore, FalconStor, StorAge, ...) and now wants to support OpenVMS. Good luck.

[Robert Jacobs]

Thank you Robert Brooks

The co-worker is in UK/Germany I do not have direct contact

I was just wondering if somebody had some additional info on how the EVA products pass the Virtual disk ID i.e UDID to the console level sho device and then up to OpenVMS. etc... I did touch base with another ex coworker at my last job and he indicated the HP SAN appliance once configured with VDISKS will presents this info to the OpenVMS cluster without any SET ID command like you would do at a HSG-80


Can you add any more helpful notes UWE?

[Uwe Zessin]

The (AlphaServer SRM/WWIDMGR) UDID, (HSG unit) IDENTIFIER, (EVA) OS Unit ID - unfortunately this mechanism has different names at different locations - is a value in a vendor-specific SCSI page I have been told.

The EVA storage management system (often called SAN Management Appliance) is not involved, except it is used to assign a value to a virtual disk by one of the management tools.