Re: stretching HACMP
Date: 8 Aug 2003 04:44:02 -0700
Patrick Agsten <firstname.lastname@example.org> wrote in message news:<vHvYa.2$Ua3.509@psinet-eu-nl>...
> Hi there,
> I want to stretch a HACMP cluster. Assuming a FFFFFF00 netmask my
> current configuration consists of two nodes A and B. A has boot address
> 10.23.10.11 and standby address 10.240.10.11. B has boot 10.23.10.12 and
> standby 10.240.10.12. The service addresses are from the same subnet as
> the boot addresses are, say .15, .16, .17 for A and .25, .26, .27 for B.
> The cluster members are directly connected through layer-2 networking
> elements. Heartbeat is made over RS-232.
> My theory is that the same should work within different subnets if I
> tell the layer-3 networking elements to set the appropriate routes. I
> discussed that with our networking staff and they see no problem with
> the routing. So the question is what happens to the cluster if the
> layout is boot 10.23.10.11 for A and boot 10.23.20.11 for B. Standby are
> 10.240.10.11 for A and 10.240.20.11 for B. All with netmask FFFFFF00.
> The service addresses are in the same subnet as the boot addresses of
> the primary cluster member. One problem at far distances is the RS-232
> but this can be solved using SSA adapters with optical extenders. For
> all communication within the cluster should be TCP/IP based this layout
> should work if the network makes sure that all addresses are reachable.
> Has anyone done something like this before or is there any opinion to
> the theory that would help me?
We have several clusters using fibre optics to extend the geographical
distance. I would suggets that if fibre is available why not simply
extend your network also making the setup the same as you have now
just over a greater distance?
You will also need to consider changing some of the configuration of
the HACMP as you should mrrir between sites and you need to consider
what effect a site down will have ( it should require a force varyon?
). Also remember to configure target mode SSA to supply HACMP with an
alternative network other than tcpip.
If you do go the router and routes option remember to set the cluster
to low heartbeat rate as the time to send and receive packets will
increase ( HA heartbeats over all available networks ).