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Two types of cluster upgrades are available: a concurrent upgrade and a rolling upgrade. The type of upgrade you use depends on whether you want to maintain the availability of the cluster during the upgrade and whether you have more than one system disk. Review this chapter and then perform the preliminary tasks for the upgrade procedure (concurrent or rolling) that best suit your configuration.

5.5.1 Concurrent Upgrade

This section describes the following:

How a concurrent upgrade works
Preparing your system for a concurrent upgrade

5.5.1.1 How a Concurrent Upgrade Works

During a concurrent upgrade, you must shut down the entire cluster and upgrade each system disk. No one can use the cluster until you upgrade each system disk and reboot each computer. When the cluster reboots, each computer will run the upgraded version of the OpenVMS operating system.

If all systems in the OpenVMS Cluster environment are booted from one system disk, you must perform a concurrent upgrade.

5.5.1.2 Preparing Your System for a Concurrent Upgrade

To prepare for a concurrent upgrade, follow these steps:

Log in locally to the SYSTEM account.
If you have more than one system disk, make sure that you have performed the preupgrade tasks on each system disk that you are upgrading. Make sure the target system disk is not mounted on any other node in the cluster and remains dismounted during the upgrade. It should be mounted only on the system that is performing the upgrade. (For information about dismounting disks, see Section 5.5.2.3.) Then go to Chapter 6 and perform an upgrade on each system disk. You do not have to reboot the operating system media for each upgrade. You only need to choose option 1 on the menu for each upgrade.
Shut down all systems by entering the following command on each system (satellite nodes first, then the boot nodes):
$ @SYS$SYSTEM:SHUTDOWN
When the procedure asks whether an automatic system reboot should be performed, enter N (NO).
After all satellite nodes have shut down, select the CLUSTER_SHUTDOWN option.
When the shutdown procedure is finished on all nodes, halt each system by either pressing Ctrl/P or Halt. For more information about halting your Integrity servers, see Section B.7.1. For information about halting your Alpha computer, see Section A.3.1.
If you have only one system disk for your cluster, go to Chapter 6 to begin the upgrade procedure.
After the upgrade is complete, you are instructed to reboot each computer in the OpenVMS Cluster environment before beginning other postupgrade procedures.

5.5.2 Rolling Upgrade

This section describes the following:

How a rolling upgrade works
Notes and restrictions
Preparing your system for a rolling upgrade

5.5.2.1 How a Rolling Upgrade Works

A rolling upgrade allows you to have a mixed-version cluster. During a rolling upgrade, you keep some of the computers in the cluster running and available while you upgrade others. You must have more than one system disk. You upgrade each system disk individually, allowing old and new versions of the operating system to run together in the same cluster.

5.5.2.2 Notes and Restrictions

The following restrictions apply to rolling upgrades. For additional compatibility issues and restrictions information, see the HP OpenVMS Version 8.4 Release Notes.

The system being upgraded must not attempt to access any disk that is being accessed by one or more of the remaining OpenVMS Cluster systems.

The remaining OpenVMS Cluster systems must not attempt to access the target disk of the system being upgraded.

If the target disk being upgraded is locally attached to the system performing the upgrade, then it is not accessible to the remaining OpenVMS Cluster systems. (The OpenVMS system booted from the operating system media does not MSCP serve local disks.) HP recommends that, whenever possible, you perform the upgrade on a local disk or that you perform a concurrent upgrade.

During the upgrade, be sure that the target disk you select, as well as any disk you access from the DCL menu option, is either a local disk or one that is not being accessed by any of the remaining OpenVMS Cluster members. Make sure the target system disk is not mounted on any other node in the cluster and remains dismounted during the upgrade. It should be mounted only on the system that is performing the upgrade. (For information about dismounting disks, see Section 5.5.2.3.)




	NOTE: Any attempt to access the target system disk from the remaining OpenVMS Cluster members will corrupt the target disk. Even if the target system disk is mounted only by a remaining cluster member and no file access is performed, the target disk will probably be corrupted. If a disk is corrupted in this way, the only supported recovery is to restore the backup copy of the corrupted disk.

HP recommends that all Alpha computers in a cluster run the same (preferably the latest) version of the OpenVMS Alpha operating system, and that all Integrity servers run the same version of the OpenVMS Integrity servers operating system.
You cannot perform a rolling upgrade if all systems boot from a single system disk. Perform a concurrent upgrade instead.
The upgrade procedure affects the queuing system as follows:
- The queuing system is not active on the system you are upgrading; do not attempt to execute a START/QUEUE/MANAGER command.
- You cannot create a queue database on the operating system CD/DVD (because it is not writable).
- The queue manager process on other nodes in the cluster can continue to run during the upgrade if the queue database is not on the disk being upgraded.

5.5.2.3 Preparing Your System for a Rolling Upgrade

To prepare for a rolling upgrade, follow these steps:

Log in to any node where the target disk is mounted as a data disk rather than as the system disk. (That disk must be the one on which you already performed the preupgrade tasks described in Chapter 4.)
Check the votes and make adjustments to maintain the proper quorum so the cluster can continue to operate throughout the upgrade. (HP OpenVMS Cluster Systems describes this procedure in detail.)
Use the DCL command DISMOUNT/CLUSTER to dismount the data disk. (You can also perform this operation using the SYSMAN utility.)
Note that you can ignore messages from nodes where the specified data disk is being used as the system disk.
Verify that the data disk has been dismounted successfully by entering the following commands:
$ MCR SYSMAN SYSMAN> SET ENVIRONMENT/CLUSTER SYSMAN> DO SHOW DEVICE disk-name
Examine the display to be sure the disk is not mounted on any nodes as a data disk. Noting the value listed in the Trans Count field can help you make that determination: A value of less than 50 indicates that the disk is mounted as a data disk rather than as the system disk; a much larger value (for example, 300) indicates that the disk most likely is the system disk.
If the disk is still mounted on any nodes as a data disk, use the SYSMAN utility to dismount the disk; otherwise, exit the SYSMAN utility.
Use the following command to shut down any nodes that boot from the system disk you are upgrading (shut down satellite nodes first):
$ @SYS$SYSTEM:SHUTDOWN
1. When the procedure asks whether an automatic system reboot should be performed, enter N (NO).
2. After all satellite nodes have shut down, select the REMOVE_NODE option.

If a proper quorum is not maintained at any time during the upgrade procedure, the shutdown procedure hangs the cluster. If the cluster hangs during a shutdown, you can use the Interrupt Priority C (IPC) facility to adjust quorum from the system console of a system that is still a cluster member.

From an OpenVMS Alpha cluster member, press Ctrl/P. The IPC facility displays help information about IPC commands. Enter the commands at the console:

$ Ctrl/P
>>> D SIRR C
>>> C
Interrupt Priority C

Commands:

  C device    Cancel Mount Verification
  Q           Adjust Quorum
  CTRL-Z      Exit IPC
  CTRL-P      Prompt for Crash
IPC> Q
IPC> Ctrl/Z

From an OpenVMS Integrity servers cluster member, pressing Ctrl/P puts the system directly into the IPC facility, which displays help information about IPC commands. To adjust quorum, enter the commands shown in the following example. Note that if systems are booted with XDELTA, pressing Ctrl/P brings the OpenVMS Integrity servers system into XDELTA. The IPC facility is not available in this case.

$ Ctrl/P
Interrupt Priority C

Commands:

  C device    Cancel Mount Verification
  Q           Adjust Quorum
  CTRL-Z      Exit IPC
  CTRL-P      Prompt for Crash
IPC> Q
IPC> Ctrl/Z

You can also adjust quorum using Availability Manager or DECamds. The method is equivalent to that used by IPC except you do not have to use the console (this assumes the Data Analyzer is running on a system outside the OpenVMS Cluster, which is recommended). For more information, see the “Adjust Quorum” section in the Availability Manager User’s Guide or the DECamds User’s Guide. The Availability Manager User’s Guide is available at:

http://www.hp.com/products/openvms/availabilitymanager

After the shutdown procedure is finished on all nodes, go to Chapter 6 to begin the upgrade procedure.




	CAUTION: During the upgrade it is very important that the system disk being upgraded is accessed only by the node on which the upgrade is being performed. If the disk can be accessed from other nodes in the cluster, for example, through an HSC or HSJ device, you must ensure that this does not happen. Even if the disk is only mounted and no file access is performed, the disk can still become corrupted. Ensure that any users who might mount disks know that they must not access the system disk being upgraded. Also make sure that any procedures that might mount the disk do not run during the upgrade. If you have automatic procedures that periodically check and remount disks, it would be wise to disable them during the upgrade.

HP OpenVMS Systems Documentation