VMScluster with AXP 7.3-2 and I64 8.3-1H1

[Bo Midberg]

In the 8.3-1H1 for Integrity Servers Upgrade and Installation Manual it says in section 5.3 in table 5-3 that a combination of AXP 7.3-2 and I64 8.3-1H1 is a supported migration path, but in section 5.4 it says that all Alpha and I64 nodes in the cluster must be running at least 8.3 to add a I64 8.3-1H1 member. I'm confused. Is there any reason why it is like this?

[John Gillings]

Bo,

>Is there any reason why it is like this?

It's purely an economic issue.

What "works" is usually a much larger set than what's "guaranteed to work".

OpenVMS engineering has a limited qualification budget, and the combinations and permutations of different versions and architectures in a cluster increases geometrically.

Qualification must therefore limited to a small set. Other combinations may (and most probably will) work, but engineering won't support them. Since it's a moving target, it's also possible that inconsistencies will creep into documentation.

Best practice is to keep your clusters on the same version. Usually migration support is only 1 minor version apart, but there are sometimes special exceptions. VAX V5.5-2 and Alpha V7.3-2 have some special dispensation to co-exist with some higher versions.

Regardless of what you get away with in the short term, your long term plan should be to get all systems running the same version.

[Bo Midberg]

HP support informed that 8.3 and 8.3-1H1 are the same and that they run clusters with mix of 8.3-1H1 and 7.3-2. Alas the comment that all nodes in the cluster must be at least 8.3 was not quite correct regarding adding a new node.