Hey Daniel,

I haven't done a site yet with Seaside, but I've used Smalltalk for 
public corporate web tier stuff before (insurance). I would rather have 
several less powerful machines for each application than one big 
machine. Of course, I had a paying sponsor who agreed with me that 
hardware is cheap whereas failures and programmers are expensive.

I'd prefer at least two machines per application. A failure in one 
machine/image wouldn't threaten the running application from the 
end-user perspective. Nor would it threaten other applications. I'd put 
Apache on a separate machine too. Same for the backing store (whether 
Magma -- hi Chris, GOODS, or a RDBMS). Making it so your app can run on 
several machines makes it easier to add machines to support load.

Of course, you need enough memory to handle everything. 2GB might be a 
lot or not enough, depending on what each one of those 10,000 or 500 
records are doing. Looking at just the 10000. There is probably an 
uneven distribution (different customers will have different usage 
patterns). Maybe 60% of that traffic wants to enter during your peak 
hour, so 6,000 per hour at say 1:00 P.M. local time. If they timeout at 
20 minutes...

Anyway, I would expect that the CRM and Medical systems would have very 
different usage characteristics and load patterns. The real answer is to 
test and find out. Luckily Squeak has an Http client whose guts you can 
script.

--David

> Chris,
>
> That's a very interesting perspective. The thought crossed my mind,  
> but then I thought of another "issue" which is what prompted me to  
> ask the question to the list.
>
> Originally I thought I could simply just run an image for each of  
> these specialized applications. For example, one could be a Customer  
> Relationship Management system, while the other is a Medical Billing  
> system. Both systems have different views of what a Customer is and  
> it would make sense to run them in separate images.
>
> However, given my limited resources for hardware (mainly), I wasn't  
> sure if I could, efficiently, run two Squeak images, each with  
> Seaside listening on different ports and both front-ended by Apache  
> on a single machine. I wasn't sure how two images could run on the  
> same machine in terms of performance, processes, memory, etc.  
> Assuming these would run on a dual-Xeon machine with 2GB RAM, would  
> that be feasible?
>
> To some degree, I guess the question will depend on the traffic load  
> on the machine, but I would guesstimate that, for example, the CRM  
> system would handle about 10000 contacts a day (by contact I mean  
> customer record inquiries, or logging call attempts, etc) and maybe  
> about 500 medical bill records per day. If anyone has some experience  
> in these industries, you can guesstimate some sort of traffic load.
>
> I don't k now if I'm being too vague or worrying too much about  
> something that hasn't been materialized yet. I just like to plan ahead.
>
> Thanks,
> Daniel
>
> On Jun 17, 2005, at 11:50 AM, Chris Muller wrote:
>
>>> I have two applications that both need a class Customer. However, one
>>> of the application requires that class Customer have a set of
>>> attributes and methods very different from the second application who
>>> uses the class Customer for a totally different industry.
>>>
>>
>> Hi Daniel, for me, the key to the answer to your question is the  phrase
>> "totally different industry."  If this is true, it seems there  would 
>> be little
>> chance that the Customers would need to be in the same running  
>> image, nor would
>> they need to be developed together.
>>
>> Therefore I wouldn't worry too much about trying to factor the two  
>> Customer
>> classes into a single, grand Customer superclass, if it won't ever be
>> commingled in practice.  In fact, doing so could potentially  
>> increase cost.
>> For example, the two groups of developers may have their own ideas  
>> about what
>> belongs in the generic superclass Customer.  So then you have  
>> developers
>> spending time reconciling code by two completely disparate industries.
>>
>> Even if theres a remote chance of the two programs needing to co- 
>> exist in an
>> image, you can use refactoring-tools to meld the code at that  time.  
>> But keep
>> it simpler in the meantime.  Remember, if you can solve the problem  
>> of ultimate
>> malleability of software, you no longer need to worry about up- front 
>> planning
>> of "ultimate" classes..  We still need a balance of both, but I  
>> believe the
>> future is in the former.
>>
>> That's my view, anyhow..
>>
>>  - Chris
>>
>>
>
>
>