Load-balancing with OCI connections

Gurus,
Oracle Identity Federation (OIF) can leverage an Oracle database as its transient data store in which case it uses JDBC-OCI connections to connect. However, there is no provision in OIF of defining multiple databases for load-balancing purposes.
Is this achievable using some load-balancer in front of multiple database instances and using a virtual hostname/IP in tnsnames.ora which OIF refers to?
-Vinod

I would say that using two seperate databases (with replication)
as the backend would mean that one database, at any time,
might be lagging the other, depending on which tables are updated
and how replication is implemented.
Connect Time Failover, rather than Load Balancing, might be an
implementation -- to handle Instance Failure (eg node / site has gone down).
Instead of Load Balancing.
Load Balancng between two seperate databases would be usable
if you are sure that either of
a. The underlying data doesn't change
OR
b. The application and users are aware that they might see different data
if there ARE changes to the data, not yet synchronised between the two DBs.

Similar Messages

Failover and Load Balancing with JNDI Connection Pools

Hi,
I am trying to figure out how would JNDI Connection Pooling work along with failover or DNS Load Balancing.
Would connections be distributed equally among the list?
Would the pool work with multiple heterogeneous connections (i.e. connections to different but equivalent servers ), or do all the connections in the pool have to be homogeneous (i.e. to the same server)?
Thanks,
Sergio

Hi,
I am trying to figure out how would JNDI Connection Pooling work along with failover or DNS Load Balancing.
Would connections be distributed equally among the list?
Would the pool work with multiple heterogeneous connections (i.e. connections to different but equivalent servers ), or do all the connections in the pool have to be homogeneous (i.e. to the same server)?
Thanks,
Sergio

Load balancing 10g forms - Connection from new browser window not supported

Load balancing 10g forms - Connection from new browser window not supported
We're experimenting with using webcache to load balance between multiple applications servers running OC4J forms processes.
We currently have one machine with infrastructure and mid-tier (BI & Forms) installed, which is being used for the webcache functionality, this is load balancing between 2 other servers each of which just have the mid-tier (BI & Forms) installation
In order to get this to work, I had to follow the instructions in the Forms deployment guide : http://download-uk.oracle.com/docs/cd/B14099_11/web.1012/b14032/tuning.htm#sthref707
The main gist of this is that you need to set the following in the orion-web.xml file in order that the sessions are maintained:
<session-tracking
cookies="enabled">
</session-tracking>
This all works fine in most cases.
The problem I am having is if I do one of the following on the client machine:
1) From IE6 / IE7 run a copy of a forms application. Then open a new window using the "New Window" menu option, and attempt to run another forms application.
2) In IE7 or Firefox 2.0 open a copy of the forms application, and then open a new tab and try and open another forms application.
If I try either of these I get a FRM-92101 error, and the following is displayed in the java console:
oracle.forms.net.ConnectionException: Connection from new browser window not supported
From trawling various forums (including metalink and otn) it looks like a problem with the way coockies are handled.
Unfortunately the usual workaround is to ensure that the session tracking option in the orion-web.xml file is disabled.
The problem is that I need this enabled in order for the load balancing to work.
Does anyone know of any other workarounds or patches that might help resolve this?
We're using Application server 10.1.2.0.2 running on windows 2003 servers.

You were right. Carriage returns were stopping it from working (the document is laid out over separate lines, so I assumed it would make no difference...).
I've now managed to get it so the forms at least run, but they are all being run in the forms OC4J instance on the same machine as the OHS.
Has anyone actually managed to get this to work, or am I doing something wrong?
I did wonder if using an OHS instance on a machine with no forms installation would make any difference?
I had raised a support call via metalink on this subject, but they eventually came to the conclusion that the only way to do this is with a hardware load balancer (Despite several documents suggesting that webcache is the way to go (including the forms deployment manual)).
I'm at the point now of giving up and writing some custom scripts to do the job instead...

How does load-balancing with WebCache work - is there still a bottleneck?

Hello,
We're migrating an old Forms 6i app to 10.1.2.0.2 (apps servers = Redhat Linux), and are starting to consider using WebCache to loadbalance between two application servers.
My question is this - say we have apps servers A and B, both running Forms and Reports Services. We use Webcache on server A (don't have the luxury of a third apps server...) to load balance between A and B. So all initial requests come into A, which in some cases may then be diverted to start a new Forms session on B.
For those users whose middle-tier sessions are now running on B - will all network traffic for their Forms session continue to be routed through Webcache on A, then to B, over the course of the session? Or does Webcache somehow shunt the whole connection to be straight between the client PC and server B, for the duration of that Forms session?
If the former, does that mean that the server hosting Webcache can still be a significant bottleneck for network traffic? Have people found load-balancing with Webcache to be useful..?
Thanks in advance,
James

Hi gudnyc,
Thanks for posting on Adobe forums.
For HDPI you do not have to do any It will adjust automatically.
http://helpx.adobe.com/photoshop-elements/using/whats-new.html
Regards,
Sandeep

ACE 4710 and load balancing with sticky cookie

Configuring load balancing with SSL termination and stickiness for a couple of citrix xenapp servers. I'm doing a source-NAT as the ACE resides in the DMZ and these particular servers reside on the inside arm of the firewall. The ACE is in bridged mode to load balance web servers that reside in the DMZ. Everything seems to work just fine, but the cookie stickiness does not seem to be working.

Hi David,
As you may know, using Wireshark to look at an HTTPS capture is only useful if you've installed the server SSL key.This is why I find it easier to use something like LiveHTTPHeaders or HTTPWatch.
When using cookie-insert, the ACE will not create any dynamic cookie entries. It will simply create one static entry for each rserver with a cookie value, such as R3911631338, and any client that gets load balanced to that rserver will receive a cookie with that value. So what you see there is what is expected.
You are correct in that when using location cookies that the server supplies, the ACE will create a dynamic entry when it sees the server response with the cookie. The cookie is included in the server's response, and the ACE will look for the value as configured. The cookie will also be sent to the client. If the cookie is not in the server's first response, you will need enable persistence-rebalance so that it will look in subsequent server responses. If the browser opens new connections with that cookie, then the ACE will stick to the same server.
My suggestion would be to get sticky working with cookie-insert first. Then if that meets your needs, go with that permanently. If you need to use server cookies, then once cookie insert is working, migrate your sticky to cookie location.
Sean

T3 Load Balancing with Weblogic Server 6.1

We are using rwo weblogic 6.1 servers A and B behind a load balancer with a DNS name (eg. www.loadbalancer.com). We are using T3 for Java client to application server communication. The client creates the Initial context with the load balancer url,creates remote objects using the context, closes the initial context and then tries to get a new initial Context. What we noticed is even though the client closes the first context and gets a new one, the client is always hooked on to only one server making load balancing ineffective. Is there a T3 configuration to release the connection when we close the context ? The documentation says only one T3 is established per client JVM.

Rick,
You may want to look at the Alteon and F5 configuration we have on edocs.
Take a look at the following URLs for a possible solution
http://edocs.bea.com/wls/docs61/cluster/alteon.html#591902
http://edocs.bea.com/wls/docs61/cluster/bigip.html#591902
Chuck Nelson
DRE
BEA Technical Support

Load balancing to JDBC connection pool

from http://e-docs.bea.com/wls/docs61///////cluster/overview.html
"WebLogic Server provides limited load balancing support for managing JDBC
connections in a cluster. If you create an identical JDBC DataSource in each
clustered WebLogic Server instance and configure those DataSources to use
different connection pools, the cluster can support load balancing for JDBC
connections. Note, however, that WebLogic Server provides no special load
balancing policies for accessing connection pools. If one of your connection
pools runs out of JDBC connections, the load balancing algorithm may still
direct connection requests to the empty pool."
How is this different from creating one connection pool with one datasource
and targetting the cluster. Are they talking about load-balancing to
different databases, or different servers in WLS. from a servlet or from a
client side app?
Can anyone elaborate?
Thanks in advance.

hi,
without knowing the entire set of requirements or the motivation behind doing this, a few words from me
this is usually done transparently to the applications server, that is having eg. Oracle instances mirroring eachother for extreme high-availability requirements.
1. I would have taken the liberty of calling this business funcionality and let my middleware do the implementation of this. The most elegant solution would probably be to call the master DB for the CUD operation, then post a message to a queue letting the slave DB be updated asynchronously. If the message could not be sent, throw an exception and have the entire operation rolled back.
If however this must happen realtime and transactions must be consistent, there are a few points to consider. And the quieing bit would not work.
if this is something that should be done for all Create, Update and Delete operations, an intercepting JDBC driver could do the trick. Although there are all sorts of different problems that could arise from this, for starters, at least one of the DBMS involved here should be XA compliant. If the entire transaction should be XA compliant, both DBMS must be XA compliant. Next as for the transaction towards the "mirroring" DBMS you would have to do all the transaction stuff your self.
For an example of an intercepting JDBC driver, I found thisone
http://media.datadirect.com/download/docs/jdbc/jdbcref/spy.html
I would guess that there are quite a few more.
- [url http://blog.thej2eestruggle.com]Anders Mathisen
Edited by anders.mathisen at 01/21/2007 2:53 PM

Load balancing across database connection

Do you provide load balancing across database connections and allow RDBMS load
balancing for read only access?
Thanks in advance.

Hello, Christina.
Load balancing with multiple machines is a little bit different than
in the same machine. One of the important resource in this kind
of application is network bandwidth, so tuxedo tries to keep the
traffic among the machines as low as possible. So, it only
balance the load (call services in other machine) in case all the
services are busy in the machine where they are call.
I mean, if you have workstation clients attached only to one
machine, then tuxedo will call services in this machine untill
all servers are busy.
If you want load balancing, try to put one WSL in each machine,
and the corresponding configuration in your WSC ( with the | to
make tuxedo randomly choose one or the other) or spread your
native clients among all the machines.
And so, be carefull with the routing!
Ramón Gordillo
"Christina" <[email protected]> wrote:
>
I am looking for assistance in configuring Tuxedo to perform load balancing
across
multiple machines. I have successfully performed load balancing for a
service
across different servers hosted on one machine but not to another server
that's
hosted on a different machine.
Any assistance in this matter is greatly appreciated.

CF 10 Load-Balancing with Remote Instances

I was reading an article on Clustering/LB/HA using CF8, but have not found any updates for CF10.
Using VM VirtualBox to setup a few virtual servers, I am looking to setup a load balancing of ColdFusion 10 on 2 remote instances. The goal would be have ColdFusion Cluster Manager be able to point http request to one of the two servers based on load/availability. Not really having a hardware cluster/failover setup, just managing resources on two CF instances instead of a standalone.
The servers are Windows Server 2008 R2 with IIS7.5 and ColdFusion 10 Enterprise on installed on 3 of these machines. Let's call them CF-LBManager, CF-Web1, and CF-Web 2. In the CF Docs, they show the Cluster Manager adding the local CF instance and "if you want" a remote instance. However, this scenario would require the main instance to be running and not fail for it to direct to the other instance.
I am trying to set this up now with CF-LBManager as just a manager of the requests coming in. In the Enterprise Manager >> Instance Manager, the local instance is shown and I add the two remote instances with the correct Remote Port, JVM Route, etc. I also made sure the <Cluster>...</Cluster> block was added to the two remote instances (CF-Web1 and CF-Web2) \runtime\conf\server.xml file too, Jetty Services also is running. Now under the Enterprise Manager >> Cluster Manager I add the two remote instances to the cluster, not the local instance on CF-LBManager with Multicast Port and Sticky Sessions enabled. On Submit, I get a green message "You must restart all the server instances and any configured webservers for these changes to take effect.". I go ahead and reboot the servers and come back.
I now browse to the ColdFusion page as a test on CF-Web1 and CF-Web2 to make sure CF is running properly, they do. I then browse the IP of the CF-LBManager, however it only returns the local IIS web site and not redirect to one of the two cluster members. I am not seeing any message on the coldfusion-out.log on the remote instances. Am I not setting this up correctly or not enabling the Cluster Manager to take over and pass along the requests to those in the cluster?

Unfortunatley I don't have a lot of experience with CF10 on Windows, but if you are running CF behind IIS I think you will need to update the Tomcat connector configuraiton to do load balancing. I'm not sure if re-running the wsconfig tool on all of the servers will do this or not, but that is what I would suggest trying first. If that doesn't work you will need to update the Tomcat connector configuraiton manually. You can find more information on load balancing with the Tomcat connector here: http://tomcat.apache.org/connectors-doc/generic_howto/loadbalancers.html.

CSS Load Balancing with Cookies

We are trying to load balance 2 backend servers hosted on Websphere with advance balance cookies method.
Restrictions
ServerA is unable to accept cookies generated from ServerB.
ServerA and ServerB are generating random cookies
Unable to modify cookie string with a constant.
How can we load balance based on cookies considering the above restrictions?
We have attempted to do hash based load balancing with cookies but the problem we run into is the servers do not accept cookies generated from another server.
The configuration we tried is written below:
service ServerA
ip address 192.168.10.2
keepalive type tcp
keepalive port 80
active
service ServerB
ip address 192.168.20.2
keepalive type tcp
keepalive port 80
active
content ABC
url "/*"
add service ServerA
string prefix "JSESSIONID="
advanced-balance cookies
port 80
add service ServerB
string skip-length 5
string process-length 16
string operation hash-xor
protocol tcp
vip address 172.16.32.1
active
Can we change the string prefix to JSESSION instead of JSESSIONID= ?
The only place the app guys can add a constant string to match on is before the = sign.
Is it possible for CSS to match on a constant string before = sign e.g below:
service ServerA
ip address 192.168.10.2
keepalive type tcp
keepalive port 80
string id567=
active
service ServerB
ip address 192.168.20.2
keepalive type tcp
keepalive port 80
string id123=
active
content ABC
url "/*"
add service ServerA
string prefix "JSESSION"
advanced-balance cookies
port 80
add service ServerB
string skip-length 0
string process-length 6
protocol tcp
vip address 172.16.32.1
active

It should work.
There is no reason for it not to work...
This is the best method you can have on the CSS for stickyness.
Get a sniffer trace on the client and server with arrowpoint cookie configured on the CSS and capture a failure so we can see what is going on.
also send me the config so I can verify everything is ok.
If you have a service request open with the TAC, you can also give the SR # so I can review what has been done.
Gilles.

Cache and Load Balancing with Oracle APEX Listener

Hi,
I intend to use only HTTP access.
How to implement a Cache and Load Balancing with the Oracle APEX Listener?
Is it possible to do with the the standalone running APEX Listener?
Thanks by advance for any tips/documentation/references.
Kind Regards.

Hi,
I think this question is best asked in the APEX Listener forum:
ORDS, SODA & JSON in the Database
Kind regards
Sandro

Load balancing with JSP

Anyone and everyone,
When configuring load balancing with Weblogic clusters, does load
balancing take effect for all services or just EJB and RMI? Or another
way of saying the same thing, can I setup weighted load balancing for
the JSP engines across 2 weblogic servers.
Thanks in advance,
Mike

The load-balancing documentation you read describing the different algorithms only applies to RMI stubs (e.g., EJB clients). Please see http://www.weblogic.com/docs51/cluster/concepts.html#1026091 for a description of how load-balancing/clustering works with servlets/JSPs.
The short answer is that in using servlet clustering, most people want/need/use in-memory replication for HttpSession objects. In WLS 5.1 (and before), in-memory replication requires one or more proxy servers be set-up in front of the cluster. Typically, most people use something like BigIP to load-balance
across the proxy servers and let the weblogic plug-in for the proxy server handle the routing to the cluster. The plug-in uses round-robin until an HttpSession is established for a user, then it always tries to route to the server where the user's session is located.
Hope this helps,
Robert
Brian Lin wrote:
All,
I have a quesiton here regarding load balancing with DNS round robin. As of Chapter Adminstration of Clustering Weblogic server, Weblogic can be configured to balance by weight. How about Weblogic handle weight based balancing after DNS round robin ip response? or just can choose one way instead of both?
What's the big difference between choosing BigIP and software balancing (WL)?
Brian
"Wei Guan" <[email protected]> wrote:
I don't think you can configure this load balancing in weblogic in current
release. However, if you have Big-IP or LocalDireoctr, you can set up
weighted load-balancing there. Otherwise, weblogic proxy will use DNS round
robin to do the load-balancing between JSP engins.
My 2 cents.
Cheers - Wei
Michael Yakimisky <[email protected]> wrote in message
news:[email protected]...
Anyone and everyone,
When configuring load balancing with Weblogic clusters, does load
balancing take effect for all services or just EJB and RMI? Or another
way of saying the same thing, can I setup weighted load balancing for
the JSP engines across 2 weblogic servers.
Thanks in advance,
Mike

Multihomed eBGP load balancing with 3 ISP's

We currently peer with 2 ISPs using BGP in an active/failover configuration. My company wants to move to a 3 ISP model where Internet traffic is split across the 3 providers so that bandwidth is equally distributed on outgoing traffic across our 2 /22 ARIN IP ranges. This is from our 2 edge switches that have VSS.
Within my limited knowledge of BGP, I have determined that we could do load sharing pretty easily by adding multiple default routes and breaking up our /22's into /24 and advertising them that way. However, I don't think this satisfies the request that downtime must be seamless, should one link drop.
Currently, our ISP's advertise default routes. From the research that I've done, we could get close to load balanced links if we receive full BGP routes and community settings and definitions. I'm nervous about this because it looks really complicated, and I don't want our AS to turn into a transit AS. I've been told the same can be accomplished with only partial BGP routes and community settings and definitions.
Personally, I think we just need a WAN load balancer. However, given the request, is there a thread out there that can explain this, or can someone discuss this requested scenario a little bit?
Thanks!

Hi there
First question would be what is the required reconvergence time for the applications using the Internet? Should an outage occur, when do they lose their state? Once you know that, you then have a target to aim for in terms of recovery
With regards load-balancing, with BGP we are always talking inbound and outbound.
The outbound solution is relatively simple - each ISP advertises a default route to your Internet edge router(s). Create an eBGP session from each edge router to the core, advertise the default route and redistribute into the IGP. Ensure the IGP cost to each BGP next hop is equal and you have ECMP for outbound routing.
Inbound influence is usually via MED (not likely in this case given 3 ISPs), adjusting local-pref in the ISP via BGP EXT communities configured your end, or via AS-PATH prepending for longer prefixes from your /22. Prepending would be simplest, but your unlikely to get an exact inbound traffic split, however a relatively even distribution should be sufficient.

Load Balancing with BigIP / SSL question

I have an oddball question. We're load balancing ColdFusion
MX7 across 3 servers using a BigIP load balancing server. We
decided to go the hardware approach and it has been great except
for one small configuration issue.
We use a mix of SSL and non SSL pages, prior to the switch
from a single server to a load balanced setup I used to script that
would determine if a page that was supposed to be SSL had the
variable CGI.HTTPS turned on or off. If it was off, the page would
redirect back to itself with the SSL turned on.
The problem we have is that we followed BigIP's instruction
to secure the load balancing hardware instead of the three servers
running behind it. So what happens is that the traffic goes to the
load balancer port 441, but then the calls from the load balancer
to the individual servers is port 80. So even if a page is called
as HTTPS://... the coldfusion server says that CGI.HTTPS is "off"
since the traffic is port 80.
This isn't much of a problem, our SSL pages are linked as
HTTPS:// and the only problem would actually arise if someone was
to type in the URL and call it as HTTP rather than HTTPS.
My questions is this, does anyone know of a way that I can
detect if the page should be HTTPS and is not without changing our
configuration and putting SSL certificates on each individual
server?

Hey,
Well the load balancing with the BigIP device is really very
amazing. I think
what i liked most was swapping out servers when their lease
was up, through the
BigIP manager I just stopped all traffic to a server, shut it
down, plugged in
the new one and turned traffic back on. It was really very
easy.
The SSL stuff still gives me a headache to think about. but
I should mention I
no longer work where I was, plus now I'm all .net C# but
that's a different
story.
I think if I was going to do this all again I would not have
secured the bigIP
unit. It was nice to buy one SSL cert for all the servers I
attached rather
than one per server, but getting the SSL sites to work
properly was a headache.
We also use windows file replication where now I would go
with like a pair of
Dell MD1000's mirrored for storage and just have tons of ram
and cpu on the
front end units. Depends what you want to spend I guess. I
think the bigIP unit
we bought was like 20 grand, i think they are cheaper now
though.
Hope I helped.

Load Balancing With Round Robin

Hi,
I have two iAS instances, each on their own box, and one iWS instance
running on a third box. I have setup the web connector to use round
robin and added the server weights. I believe that is all that is to it
to do simple load balancing with iAS. The problem is is that the
requests only go to one iAS instance. The server weights are 1 and 1.
Am I missing something here?
Thanks

Could be lots of things.
The most common misconfiguration is testing an application that is deployed "local". This application option effectively disables load balancing.
Another common mistake is to either not update the configuration of the webconnector (if the webconnector
has a seperate configuration LDAP) or to not restart
the webconnector after the configuration change.
Hope this helps. There's more things we could try, but I'll hope its one of these two easy things.

Load-balancing with OCI connections

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