I anticipate a problem that may occur when we deploy our reports on
web farms. We have reports that generate both tabular and graphic
output in a single Recordset pass. Each report page request writes a
temporary graph GIF. Subsequently, another request for the GIF is
issued due to an IMG tag on the report page: <IMG
SRC="IMG.asp?graph123.gif"> IMG.asp responds with the GIF that was
generated by the report page request. The problem I anticipate is that
requests for GIF files may be directed to different servers on the web
farm than the server on which the GIF is written, resulting in a "File
not found" error from IMG.asp. It could be solved by having IMG.asp
generate the GIF by reissuing the query but this would double SQL
Server's workload. Using a network drive to store the GIF could also
solve it but this is not an option because network share access will
be disabled on the web farm for security reasons.

Is this a problem? Does it depend on the type of web farm and/or web
farm configuration? Is there a work around that can coerce requests
for the graph GIFs back to the same server?

Thanks in for any insights,
Paul Sullivan

RE: Can requests for page parts be coerced to the same server by timcof

timcof
Mon Nov 10 04:16:00 CST 2003

Affinity set on your load balancer should handle this, I would think. If set properly, this ensures that the same client always gets back to the same server in
the farm.

Thank you. I hope this information is helpful.

Tim Coffey [MSFT]

This posting is provided ?AS IS? with no warranties, and confers no rights. You assume all risk for your use. © 2001 Microsoft Corporation. All rights reserved.
--------------------
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| Newsgroups: microsoft.public.inetserver.iis
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|
| I anticipate a problem that may occur when we deploy our reports on
| web farms. We have reports that generate both tabular and graphic
| output in a single Recordset pass. Each report page request writes a
| temporary graph GIF. Subsequently, another request for the GIF is
| issued due to an IMG tag on the report page: <IMG
| SRC="IMG.asp?graph123.gif"> IMG.asp responds with the GIF that was
| generated by the report page request. The problem I anticipate is that
| requests for GIF files may be directed to different servers on the web
| farm than the server on which the GIF is written, resulting in a "File
| not found" error from IMG.asp. It could be solved by having IMG.asp
| generate the GIF by reissuing the query but this would double SQL
| Server's workload. Using a network drive to store the GIF could also
| solve it but this is not an option because network share access will
| be disabled on the web farm for security reasons.
|
| Is this a problem? Does it depend on the type of web farm and/or web
| farm configuration? Is there a work around that can coerce requests
| for the graph GIFs back to the same server?
|
| Thanks in for any insights,
| Paul Sullivan
|