OpenVMS freeze after editing VM config in ESXi to add new vdisk

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ztang
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OpenVMS freeze after editing VM config in ESXi to add new vdisk

Post by ztang » Thu May 18, 2023 10:17 am

Hi guys,

I am getting this issue with OpenVMS:

When VM is running, edit the VM config through ESXi webpage and add a new virtual disk, the VM will freeze.
Reset the VM will bring it back to normal state with the new disk visible.

Same operation does not cause freeze issue in Ubuntu Linux 22 in the same set up.

Any similar experience / thoughts?
Is this expected behavior with OpenVMS, or is there something we missed?


pjacobi
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Re: OpenVMS freeze after editing VM config in ESXi to add new vdisk

Post by pjacobi » Wed Jun 28, 2023 12:43 pm

The freeze/hang as a result of a ESXi hot-add of a SATA disk is a result of a Port Change interrupt that is not acknowledged producing a repeated interrupt to the SATA port driver. I have a fix for the driver to properly acknowledge the Port Change interrupt and resolve the system freeze/hang. This fix will likely be made available in a future patch kit.

Unfortunately, the VMS SATA driver was not designed for Hot-add of SATA devices. There are substantial changes needed to the driver to implement Hot-add functionality. The work is under investigation for a future release. For now, VMS has the restriction that the VM must be powered-off before adding a SATA device.

Current efforts are focused on Fibre Channel Pass-through on X86. The Qlogic HBA driver fully supports hot-add of new storage controller LUNs, i.e. ($x$DGAxxxx) disks. QLogic Fibre Channel Hot-add of LUNs will likely be released before Hot-add of SATA devices.


Paul A. Jacobi
VMS Software, Inc.


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Re: OpenVMS freeze after editing VM config in ESXi to add new vdisk

Post by pjacobi » Thu Aug 03, 2023 10:14 am

If you need hot-add/hot-delete capability today on ESXi, I have found that this seems to work correctly using the LSI parallel SCSI adapter. Be sure to power-off the VM and add the SCSI adapter and this parameter so that the SCSI adapter is configured correctly:

efi.quickBoot.enabled = FALSE

When a disk is hot-added to the SCSI controller, the serial port will lose connection. This seems to be an ESXi problem. Re-connect to the serial console and VMS will still be running. Configure the new SCSI device by:

$MCR SYSMAN IO AUTO

It will now be possible to INIT and MOUNT the new DK device.

Prior to hot-delete, be sure to DISMOUNT the disk. Disks that have been deleted will still appear with on-line status, but an error will be produced if any attempt to use them.

This is the exact same behavior as a bare metal system with SCSI enclosure and removable SCSI disks.

ESXi is the only hypervisor that I know that supports hot add/delete of disks.


Paul A. Jacobi
VMS Software.

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