[Openroad-users] OR App Server Architecture Design

[Jonathan Barton]

Many thanks each of you for all your help.
 
I have decided to keep a linear design and have a designated App Server
for each web server without using the remote nameserver entries and rely
on the web server for the load balancing.  
 
We actually have separate servers for the OR App Server and the Web
Services (so will be 4 servers in total).
 
With regards to the run-time failover to the 2nd App Server, we add the
App Server connections to the web server cache so that we do not connect
every time.  We have found this speeds up the total time taken for each
call.  I am reticent to remove this caching to have automatic failover
to the 2nd App Server.  If one App Server fails I can amend the server
referenced in the config file and clear the cache by running iisreset.
Saying that automatic failover is a desirable option. I will think about
it some more and carry out further testing.
 
Sorry if this is getting into the realms of a .net discussion! :-)
 
Thanks again.
 
JONATHAN

________________________________

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Fabian
Anderson
Sent: 19 September 2007 22:55
To: International OpenROAD Users
Subject: Re: [Openroad-users] (no subject)



Hi Jonathan,

            I think there is some benefit in only using local nameserver
entries on the App Server.  If you consider each web server as a node,
then having the Web Server only use the local app server will still
achieve the load balancing and redundancy required.  If any part of the
request fails, the Web Server will "fail-over" to another Web Server
(and its local App Server).  By allowing remote nameserver entries, you
have to secure an extra layer of your application for network access and
you may also have extra network traffic.  

            If the only Client of the App Server is a local process
(i.e. A Web Service on the same machine), then having Remote App Server
nodes just introduces extra complexity without much (if any) benefit.
If you are considering the performance aspect, I think it would be
considerably reduced under high load as all threads on all nodes will be
busy and introducing extra IO and network protocols is only going to
reduce the available resources.

            Another point is that if the App Server returns large
amounts of data to the Web Services, then all of that IO will happen
over the network with remote nameserver entries instead of in memory
(which is also much faster).  You need to consider the cost of
introducing redundancy/load-balancing at every layer.  For example, for
Web Servers, where most of the source files are read-only anyway, is
there any benefit in introducing a distributed file system?  If it is a
benefit and the option is taken, it will reduce the overall available
resources.  

 

Cheers,

Fabian Anderson

Systems Analyst / Programmer

Fintechnix Pty Ltd

 

 

 

 

________________________________

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Jonathan
Barton
Sent: Wednesday, 19 September 2007 18:50
To: International OpenROAD Users
Subject: [Openroad-users] (no subject)

 

Hi all

 

I am looking for a bit of advice OR App Server architecture deisgn.

 

We have two web servers (resiliance/load balancing with .net Web
Services) both of which communicate with an OpenROAD Application Server,
and all is well.

 

I have been testing the use of an additional OR App Server using remote
nameserver entries on the primary OR App Server for resiliance purposes
and I am ready to deploy the new server to the live environment.  But I
am concerned about practicalities of effective resiliance and software
releases requiring down-time.

 

Is there any benefit of not using the remote nameserver entries on the
Primary OR App Server, but rather have a designated App Server for each
web server?  This would enable us to deploy new software without taking
the system off-line by simply draining a web server from our nlb
(Windows 2003 Network Load Balancing).  Although this would not be true
load balancing as far as the App Server is concerned.

 

Any experience shared would be greatly appreciated.

 

Many thanks.

 

JONATHAN

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"University of the West of England"

* Work Email:         jonathan.barton at uwe.ac.uk

* Work No:             0117 3281075

 

P Please consider the environment before printing.

 

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