NLB with Affinity & AOL

[SevDer]

Hi we just setup the NLB with affinity set to class C, however we are sure
that a lot of AOL users are switching machines when they are in process and
as a result, sessions are lost.

The reason we think is because, AOL users IP addresses can change between
requests and even the address change is sometimes not in the same subnet.

How can we solve this problem with maintaining affinity.
Please help ASAP.

[WenJun Zhang[msft]]

Hi SevDer,

If the class C range still changes for AOL users, you may need to enable
Request Forwarding in applciation center:

286279 How To Handle Web Client Session State in an Application Center 2000
Cluster
http://support.microsoft.com/default.aspx?scid=kb;EN-US;286279

Otherwise, out of process session is required like ASP.net state server or
SQL mode. Thanks.

Best regards,

WenJun Zhang
Microsoft Online Partner Support

This posting is provided "AS IS" with no warranties, and confers no rights.

[SevDer]

Hi,

Changing to out of process session will save our session variables, but what
will happen to our cache object data, application object data and static
variables?

Also below article is for Application Center 2000, I didn't see anything
regarding "request forwarding" in Windows 2003 Server NLB settings.

Thanks for the information
--
SevDer
http://www.sevder.com
A new source for .NET Developers

Post by WenJun Zhang[msft]
Hi SevDer,
If the class C range still changes for AOL users, you may need to enable
286279 How To Handle Web Client Session State in an Application Center
2000
Cluster
http://support.microsoft.com/default.aspx?scid=kb;EN-US;286279
Otherwise, out of process session is required like ASP.net state server or
SQL mode. Thanks.
Best regards,
WenJun Zhang
Microsoft Online Partner Support
This posting is provided "AS IS" with no warranties, and confers no rights.

[WenJun Zhang[msft]]

Hi SevDer,

Only session state can be maintained in OOP(out of process) mode. Other
variables like application will be lost.

Pure NLB doesn't have the ability of request forwarding. If Class C
affinity isn't enough, you should consider using Application Center
cluster. Thanks.

Best regards,

WenJun Zhang
Microsoft Online Partner Support

This posting is provided "AS IS" with no warranties, and confers no rights.

[SevDer]

Thank you for your inputs.

By the way, what is the projected loss in performance when we try to use
request forwarding? (In the link you've sent, it says it is time consuming
operation) We are using 2 dual core CPU's with 3.5GB ram on each on the
machines (3 NLB machines)

Thanks again for your help.
--
SevDer
http://www.sevder.com
A new source for .NET Developers

Post by WenJun Zhang[msft]
Hi SevDer,
Only session state can be maintained in OOP(out of process) mode. Other
variables like application will be lost.
Pure NLB doesn't have the ability of request forwarding. If Class C
affinity isn't enough, you should consider using Application Center
cluster. Thanks.
Best regards,
WenJun Zhang
Microsoft Online Partner Support
This posting is provided "AS IS" with no warranties, and confers no rights.

[WenJun Zhang[msft]]

The main problem is that the Request Forwarding ISAPI filter isn't cache
aware which disable the kernel caching feature of HTTP.SYS on IIS 6.0.
Please refer to the following:

Performance Issues on Windows 2003 Server
====================================

The Request Forwarding ISAPI filter, RfFiltExt, is not cache aware, which
causes
HTTP.SYS to not cache web pages. Changing the Request Forwarding ISAPI
filter to
be cache aware it not supported.

Events and Conditions That Disable HTTP.sys Response Caching (IIS 6.0)
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/c
66205c7-
8e96-4b07-98fd-1036831abf08.mspx
There is an ISAPI filter installed that is not cache-aware. By default,
ISAPI
filters are not cache-aware, but you can set the FilterEnableCache metabase
property for the filter to make it cache-aware. All filters that are
included with
IIS 6.0, including FrontPage and ASP.NET filters, are cache-aware.

If Request Forwarding is not used (usually it is not), remove the Request
Forwarding ISAPI filter (RfFiltExt). This will result in better
performance and
will avoid possible problems with the web server not functioning. After
making
this change, the Request Forwarding options will not be displayed in the
Application Center MMC.

820453 Application Center 2000 does not perform as well on Windows
Server
2003
http://support.microsoft.com/?id=820453

262674 How to remove the Request Forwarder ISAPI
http://support.microsoft.com/?id=262674

BUG: The Request Forwarding Property Page on the Application Center UI
Is Not
Enabled After the RfFiltExt Filter Is Removed
http://support.microsoft.com/default.aspx?scid=KB;EN-US;821110

HTTP.SYS Articles
===============

What's New in Internet Information Services 6.0
http://www.microsoft.com/windowsserver2003/evaluation/overview/technologies/
iis.mspx

Windows Server 2003 introduces a new kernel-mode driver, HTTP protocol
stack
(HTTP.sys), for HTTP parsing and caching, providing increased scalability
and
performance. IIS 6.0 is built on top of HTTP.sys and is specifically tuned
to
increase Web server throughput.

New Features Improve Your Web Server's Performance, Reliability, and
Scalability
http://msdn.microsoft.com/msdnmag/issues/02/03/IIS6/default.aspx
Http.sys implements a URI response cache. By implementing a cache, the
service
handle caches HTTP responses completely in kernel mode with no transition
to user
mode, thereby greatly improving performance.

HTTP Protocol Stack (IIS 6.0)
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/a
2a45c42-
38bc464c-a097-d7a202092a54.mspx

INF: Http.sys Registry Settings for IIS
http://support.microsoft.com/?kbid=820129

Best regards,

WenJun Zhang
Microsoft Online Partner Support

This posting is provided "AS IS" with no warranties, and confers no rights.