[Info-vax] Third node into 2-node cluster

[Stephen Hoffman]

On 2019-03-26 17:11:41 +0000, Phillip Helbig (undress to reply said:

> This depends on whether DECnet is installed (no, clusters don't need  
> DECnet---it's a long story).

Why is DECnet even a discussion here?   It's not like a voting host is 
likely ever using DECnet for MOP. A voting host is not going to be 
booting satellites.  Not that I'd usually even want cluster satellites 
in most production clusters.

Why do both CLUSTER_CONFIG and CLUSTER_CONFIG_LAN still exist?  Why not 
one procedure that selects the appropriate approach for the local 
cluster?

That optionally migrates the DECnet MOP data over to LANCP too and that 
allows an easier path to remove the use of DECnet, if things were 
fancier.

Why is clustering not actually integrated and the default 
configuration, with single switch that enables or disables the feature 
with the specification of the equivalent of a Wi-Fi SSID and a password?

Why are can there be a dozen or more logical names necessary for 
configuring a cluster? (That gets really fun when the UICs get skewed.)

Why?  Many are compromises and trade-offs in designs and 
implementations, and more than a few cases are fallout from 
compatibility.  Some are just your average "we didn't think that 
through" decisions.

There are many stores here. Some long. Some not so long.

The clustering integration and the user (management) interfaces could 
be better.

> The easiest way is perhaps to set up the new machine as a satellite,  
> then clone the system disk, then change MODPARAMS.DAT to make it boot 
> as  a bootserver rather than satellite.

Cloning the disk drags over piles of stuff that has to be maintained 
and updated and patched, and drags over a host name that'll have to be 
changed.

Install clean.

Drag over the cluster data and the cluster logical names and the rest 
of the baggage for a self-booting voting host, and run with a minimal 
install.

And more pragmatically, I'd probably want to migrate rx2660 boxes into 
the production position within the clusters, and not as the voting 
hosts for rx2600 boxes.  The "newer" Itanium processors usually perform 
rather better than the older cores.

And for completeness, the possibly-somewhat-less-expensive way to do 
this is a pair of TCQ-capable and multi-host capable SCSI controllers 
and a multi-initiator SCSI box.  MSA30-MI, etc.  That allows bringing a 
quorum disk online on a shared bus.  Used FC SAN might also be cheaper 
than a third (and fourth) cluster license, too.


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Pure Personal Opinion | HoffmanLabs LLC