Pure Storage FlashArray and OpenVMS

Back in the day, I used to work for Digital Equipment Corporation (DEC) and have very fond memories of the VMS and OpenVMS operating systems.

Trivia Question : When did VMS change its name to OpenVMS?

Answer: July 1992, when open systems and POSIX began to be supported.

Anyway, there are still OpenVMS systems out there today and there is a fully supported way to connect a Pure Storage FlashArray to an OpenVMS system running the Alpha or IA64 architecture.

This is only supported using Fibre Channel for connectivity and requires specific versions of OpenVMS, details of which can be found on the OpenVMS Supported Hardware list.

FlashArray requirements

There are two main requirements for volumes from a FlashArray to be visible to the OpenVMS system.

  1. The host object of the OpenVMS server on the FlashArray must have its host_personality set to vms. What this does is expose LUN 0 to the host, which is the storage system volume.
  2. The volume name must end with the string “-DGA<UDID>“, where UDID is the unique device number you allocate to the volume.

When you have fulfilled these requirements your volumes will be available for use (after re-initializing your FC cards).

Host-side volume visibility

You can see the actual volumes in a number of ways:

If you are at the Alpha console command prompt (P00>>) you can see the devices using the command wwidmgr --show wwid, but this won’t show LUN 0

The storage system volume. LUN 0, can be seen as a GGA device using the SHOW DEVICE command in DCL.

The usable volumes are also visible using the SHOW DEVIVCE command, but will be seen as DGA devices, like this
For example a volume on the FlashArray called Data-DGA200would be seen from the DCL command SHOW DEVICE DGA as like this:

Device              Device  Error  Volume  Free   Trans  Mnt
Name                Status  Count  Label   Blocks Count  Cnt
$1$DGA200: (ANAME)  Online      0

If you didn’t know, the 1 in $1$ comes from the allocation class and could be something different depending on how the operating system has been configured

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