Change the HW from 4100 with local Discs to DS25 Cluster with EVA3000 SAN

[Chris Davis_9]

Hi Manfred.

I migrated an Alpha 4100 + 2100 cluster to 2 x ES40 cluster a couple of years back. the disks were being moved from DSSI to Fibre channel via HSG60 controllers.

Once the disks were configured by our reseller, I used our standard Disaster Recovery procedures to build the new system.

We also run Adabas v4.1.1 and this is usually quite happy. You only need to make changes if the disk names where the container files are located have changed - quite possible if you're moving to an EVA, but dependent upon you're old config and whether you've used logical names.

I try to configure the system from the start so that any changes are limited to SYSTARTUP_VMS .COM, if possible, although our latest software acquisition, Attunity Connect, does store physical device names in several places, not just in its startup files.

If you have no DR procedures, I'd suggest using this exercise to develop a set of instructions. If time allows, you could use the opportunity to work out a full set of procedures.

As already mentioned, it is rarely easier to reinstall everything from scratch - too much happens over the years that you or previous managers haven't noted down. It is far easier to restore your existing system and change any parameters/device names as necessary.

I wish you success!

[John Gillings]

Manfred,

Since you're at V7.3-2, why not migrate the system with (almost) no downtime? Start with a minimal installation, temporary system disk for the DS25. Use clustering to add the new node, and make the SAN disks available to the old nodes, then use dissimilar device shadowing to move the data without interrupting processing. Once that's done, shutdown everything and boot the DS25 from the migrated system disk, AUTOGEN and reboot!

Obviously you'll need to do some detailed planning, and you will need to modify your MOUNT commands, but everything is now present in OpenVMS 7.3-2 to perform transparent physical migrations of entire data centres. With your system disk on Fibre Channel, you don't even need to have the reboot as your new node can boot from a new root on the existing system disk.

Design your clusters carefully and you'll be able to upgrade nodes, storage and sites with zero downtime!