Re: High Availability PC Based Home Automation

[Ben McCormack <yahoogroup@xxxxxxxxxxxxxxxxxxx>]

What about a Active Passive setup in vmware? Or vmotion

Ben

On 12 Feb 2009, at  08:53, Nigel Giddings wrote:

> Hi Rob,
>
>
>
> I wonder why the decision to duplicate everything has been taken?
>
>
>
> Any system is going to need occasional (?) repair and maintenance and
> there is a balance to be struck between complexity and reparability.
> Even if you go for a system that is resilient (in software) what
> happens
> when a problem does occur, and it will, and how long before a repair
> can
> be effected.
>
>
>
> It is a reality of life that failure will occur, due to mechanical,
> electrical or software failure. Sometimes due to a hidden design
> problem...
>
>
>
> I have been round this loop at home with SWMBO... The classic is
> lighting control. I have opted for C-Bus in conjunction with
> Comfort. I
> also have a PC (Server) running 24/7 providing more functionality over
> the top of this. The key being that if the PC H/W or S/W fails the
> lights still work. If Comfort were to fail, it hasn't yet, then I
> would
> lose lighting logic. Of course should a dimmer fail you would loose
> the
> associated circuits. You could argue this down to each bulb?
>
>
>
> I am comfortable that I could obtain C-Bus and Comfort spares quickly,
> less than 48 hours? I could opt to hold a full set of spares, at least
> one of each separate unit but in the case of comfort this would double
> the cost.
>
>
>
> With regard to the PC hosting the application you are probably aware
> of
> the Data Centre type servers which have built in Hardware redundancy.
> The only issue I have experienced in the past was a BIOS battery
> which I
> didn't replace in time, my problem as the H/W had been complaining
> for a
> while... I have also hot swapped a PSU and HDD with no loss of
> service.
> I run Homeseer and the biggest issue is Windows Patching.
>
>
>
> As mentioned by others a UPS should be a given with shutdown S/W.
> Also a
> lot of testing to ensure it shuts down gracefully and restarts when
> power is reapplied...
>
>
>
> Its not as exciting but I would keep things simple, and test it every
> which way... by all means have a second machine there which can be put
> into service quickly and has the benefit of allowing changes to be
> tested off network before being applied to the live network...
>
>
>
> The last thing I would say is to keep the PC H/W simple, avoid adding
> H/W such as IO cards into the machine. I prefer to connect
> everything by
> Ethernet and then the only H/W in the PC to be managed is the NIC. You
> can then sub-divide your solution, for example 1-wire via a HA7NET
> using
> Ethernet. If a repair has to be effected to the PC all the HA7NET
> support is in S/W and none in H/W (except the NIC). If, on the other
> hand, you have a 1-wire issue it is easily isolated and replaced (from
> the local spares holding?).
>
>
>
> My thoughts on resilient Home Automation....
>
>
>
> HTH
>
>
>
> Nigel
>
>
>
> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of craig
> Sent: 12 February 2009 08:16
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] High Availability PC Based Home Automation
>
>
>
>> So, people who are running PC-Based Home Automation Systems - -
what
>> lengths
>> to you go to to ensure it's always available, and how do you
>> implement
>> it?
>
> Ensure you use reliable 'branded' hardware with established drivers
&
> plugins.
>
> Use redundancy in the hardware, (eg raid, psu, etc) & UPS.
>
> Only install the bare minimum software and drivers required, after
> testing
> on a duplicate test system.
>
> Monitor the software and environment.
>
>> A potential client wants/needs a Very High Availability
> home-automation
>> solution (with Windows based software at the heart of it)- to the
>> extent
>> that he's considering purchasing 2 of every controller required
>> (CM11,
>> RAV232+, Dupline MasterGenerator, Cbus PAC etc etc) - - and
>> connecting
>> them
>> to separate servers in an active-active or active-passive
>> arrangement.
>>
>> Dedicated load balancing hardware will/may be placed "in
between".
>>
>> A Windows Cluster is one possibilty.
>>
>> 2 distinct servers set up with SQL replication is another.
>
> I think you will struggle with this unless all the software, plugins,
> network protocols, etc have been designed to be cluster aware.
> Enterprise
> software used in corporates has been designed from the ground up to be
> used
> in a cluster, to allow for scalability. Im not sure 'Home' windows
> software
> has been through the same design principles.
>
> BTW - If the client wants a highly available system, I try to would
> steer
> them away from a CM11 :)
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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