Alpha to Itanium - Dummies Guide & How was it for you?

[Troodon]

I have to say my migration was very easy with few challenges and no pitfalls. The HP OpenVMS people were _very_ helpful.

My only disappointment is that the dual cpu rx2620 IA64 machine we purchased this year has about the same performance of the last Alpha DS10 667 single CPU system we bought a few years ago, Hopefully the new multicore chips will improve things.

In retrospect, the Alphacide was a mistake, We switched from the state of the art to something short of this and lost an entire generation of performance.

[B Claremont]

As many others have suggested, review all of the relevant porting guides. They are very good. You'll find my porting experience at this link: http://h71000.www7.hp.com/openvms/journal/v6/porting_rpg_to_integrity.html

Since you are UK based, I suggest checking in with Colin Butcher at XDelta: http://www.xdelta.co.uk/

[Jan van den Ende]

Andrew,

the one option I have not seen mentioned yet, is the possibility of GRADUAL migration.

I have yet very little IA64 experience, but in the Vax->Alpha migration we have had (for YEARS) a mixed hardware cluster.

Main purpose: use IA64 to run the stuff that is qualified, but anything that is not yet available ( think about 3rd party packages etc ) can just as well be used from Alpha, operating on the same data.
Organise things well, and only System Management will be able to tell the difference, and even THEY won't care 90% of the time.

Back then we had one version of a package (DecEDI) that was never ported to Alpha. We (and our communication partners) could perhaps have done a major redefinition of our business protocols, but as it was already slated for replacement, budgets allocation was hard to get. And communication using Vax _WAS_ still working. Until the replacement was fully operational, our cluster has had one (small) Vax doing DecEDI, where all other activity was performed on Alphas.

Of course I do not know if you will run into similar issues, but if so, do not let that stop you: mixed clusters are just VMS clusters!

hth

Proost.

Have one on me.

jpe

[Colin Butcher]

That's very nice of you Bruce. Thanks.

On the whole I've found migration to be reasonably straightforward under most circumstances. From a system management perspective VMS is VMS (with a few changes if you're still on old versions such as V5.5-2 or V6.2). You'll probably need to make some radical changes to quotas and some system parameters if you're moving from a VAX or a small-memory Alpha. The EFI based console is however really quite different to anything you've seen before.

Things tend to get interesting with your porting efforts if you have any demanding and non-mainstream IO requirements, especially in real-time systems. Things also get interesting (from a floating point performance viewpoint) if you have a lot of mathematical work with large data sets that you need to access from different kinds of systems.

On the whole Itanium as an architecture is designed around plentiful memory with a lot of on-chip cache and a relatively simple CPU. Most of the cleverness is in the way that the compilers generate the instruction and data streams. Data alignment is also important for performance, so moving old VAX FORTRAN style code with large common blocks and things packed into as little memory as possible can get interesting, especially if that code has to work with old data sets, disc backed global sections and so on.

It all depends of what your systems are used for and what underlying products you rely on. In general things are usually pretty straightforward, but not always.

You might find some of the session notes here useful: http://www.xdelta.co.uk/seminars.html

Good luck.

Cheers, Colin.

[Andrew Moody_1]

Thanks everyone, for your comments so far. EFI I think I'll be ok with as I've seen it from a HP-UX perspective (which is where my experience lies).

I'm collecting papers and advice, I guess from a pure sys admin perspective it should be straight forwardish for me, it's the application developers that will have a bit more to think about.

Thanks again everyone, all your words help greatly.