[Simh] Mixed-node OpenVMS Clustering

[Norman Lastovica]

Agreed.  This cluster has real Alpha and I64 iron and 3 emulated VAXen
(not SIM in this case, but I had added SIMH nodes to this cluster as
well just for fun).

View of Cluster from system ID 44390  node: RYEROX         10-MAR-2009
08:52:16
+--------------------------------------------------------+---------+
|                         SYSTEMS                        | MEMBERS |
+--------+--------------------------------+--------------+---------+
|  NODE  |             HW_TYPE            |   SOFTWARE   |  STATUS |
+--------+--------------------------------+--------------+---------+
| RYEROX | hp AlphaServer GS1280 7/1150   | VMS V8.3     | MEMBER  |
| MALIBU | hp AlphaServer GS1280 7/1150   | VMS V8.3     | MEMBER  |
| CLYPPR | VAX 6000-630                   | VMS V7.3     | MEMBER  |
| BONZAI | VAX 6000-630                   | VMS V7.3     | MEMBER  |
| HJ50AP | HSJ5                           | HSJ V50J     |         |
| HJ50BO | HSJ5                           | HSJ V50J     |         |
| CPQ017 | AlphaServer ES40               | VMS V8.3     | MEMBER  |
| HEINLN | HP rx8620  (1.60GHz/6.0MB)     | VMS V8.3-1H1 | MEMBER  |
| QUICKR | VAX 6000-630                   | VMS V7.3     | MEMBER  |
| GIBSON | HP rx8620  (1.60GHz/6.0MB)     | VMS V8.3-1H1 | MEMBER  |
+--------+--------------------------------+--------------+---------+

> -----Original Message-----
> From: simh-bounces at trailing-edge.com
[mailto:simh-bounces at trailing-edge.com]
> On Behalf Of Hittner, David T (IT)
> Sent: Tuesday, March 10, 2009 6:35 AM
> To: SIMH at trailing-edge.com
> Subject: [Simh] Mixed-node OpenVMS Clustering
> 
> VAX and Alpha/Integrity Clustering works just fine in practice.
> 
> HP states that VAX and Integrity clustering can be done for migration
> purposes. This does not mean that they plan to take away the
> functionality - far from it. They plan to maintain cluster compatibility
> for as long as possible, because that's the whole point of clustering.
> When HP states that they don't warrant VAX-to-Integrity in production,
> it really means:
> 
> 	"HP doesn't have enough real hardware and/or time to accurately
> verify and debug all configurations. If you try it and it works for you,
> great. If you can't get it to work, we'll try our best to help, but we
> are not obligated to make it work."
> 
> The SCS Clustering protocol depends on timely and accurate multicast
> packet delivery; duplicate, dropped, or delayed packets are the killer
> of clustering. Cluster success on any slow LAN/MAN/WAN sometimes
> requires tweaking the cluster parameters, particularly the timeouts -
> the default cluster parameters are for a "standard" small-to-medium LAN.
> SIMH clustering works pretty well, as long as the host doesn't delay the
> SCS packets too long - there are ethernet device settings ("poll", etc.)
> to increase the performance of the SIMH ethernet behavior, at the
> expense of lowered CPU performance of the SIMH VAX.
> 
> Having written a lot of the SIMH ethernet code, I made sure that SIMH
> VAXes would cluster with real VAXes. After testing, I found that the
> SIMH VAX can also cluster with real Alphas. Having just added an
> Integrity to my hardware, I fully expect that clustering with the
> Integrity will work once I have time to fire the Integrity up. :-)
> 
> Dave Hittner
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