> We have a SQL Server 7 implementation with three CF servers using it as a
> database server.
>
> The problem is that it's falling over regularly (and the technical guys
> can't figure it out).
>
> That's not the problem though. We are now setting up a second
> SQL Server 7
> for use as a failover. It will replicate all of the data. My
> boss wants to
> know if it is possible for CF to use one or other of the database servers
> depending on what is up!
>
> So the idea is:
>
> For each query - check which server is up and choose one to use
> (assuming we
> can replicate all data)
>
> This doesn't make very much sense to me (it's not my idea, I just
> got asked
> to ask the list) as I would do it differently anyway!
>
> So situation (again)
>
> 2 SQL servers
> Q: can we replicate the data so they effectively are the same?
> 2 CF Server
> Q: without having to change EVERY <cfquery> can we make
> something that will
> use one or other to retrieve data depending on which one is up.
>
> Is this possible?
Warning, this is a fudge, and I wouldn't recommend doing this on a heavily
hit site...
Here's a software way to get CF to talk to whichever one you want (without
any special coding or software)
Put 2 datasources on the CF servers, one pointing to each SQL machine...
At the top of application.cfm (or the primary template) put the following
code
<cfset application.DSN="DSN1">
<cfset CanUseDSN1="No">
<cftry>
<cfquery name="testDSN" datasource="#application.DSN#">
select top 1 ID (nolock)
from table
</cfquery>
<cfset CanUseDSN1="Yes">
<cfcatch>
</cfcatch>
</cftry>
<cfif not CanUseDSN1>
<cfset application.DSN="DSN2">
</cfif>
I've left off the Locking code to keep it short, but you get the drift -
this will work, but not particularly brilliantly
It's cheap (free), but puts a tiny bit of load onto the front end of the
templates
Philip Arnold
Director
Certified ColdFusion Developer
ASP Multimedia Limited
T: +44 (0)20 8680 1133
"Websites for the real world"
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