Load balancing and High Availability topology

Our Forms 6i client-server application currently runs on Citrix farm of 20 Windows 2000 boxes (IBM Blade Servers 2 CPU and 2 Gig Memory).
Application supports 2000 users.
We are moving to AS 10g r2, forms 10g and the goal is to use same hardware, 20 Windows boxes (or less), for intranet web deployment.
What will be our best choices for application Load balancing and High Availability?
Hardware load balancer, Web Cache, mod-oc4j? Combinations?
Any suggestions, best practices, your experience?

Gerd, I understand, that you are running 10g web forms through the browser, but using Citrix for deployment. This means that in addition to Application Server and Forms runtime sessions, it will be separate browser session opened for each user. What the advantage of this configuration?
Michael, we are aware, that Citrix is not supported by Oracle as a deployment platform. That only means that prior contacting Oracle Support we have to reproduce the problem in standard environment. It was never been a problem to reproduce problem :) We were using Citrix as a deployment platform for Forms 6i client/server for 4 years, but now we are forced to upgrade to 10g.
We are familiar with various Load balancing options available. The question is which option is the most "workable" in our case.

Similar Messages

For a true load balancing and high-availability OHS, OPMN, and mod_oc4j

i have read this link of Enabling Clustering on oc4j9.0.4 standalone app server
http://www.oracle.com/technology/docs/tech/java/oc4j/htdocs/getstart.htm#1015479
To test the clustering, start up the load balancer by executing "java -jar loadbalancer.jar".
C:\OC4J_EXTENDED\j2ee\home>java -jar loadbalancer.jar
In a future release of Oracle Application Server, loadbalancer.jar will be
desupported. Because of this, we strongly suggest that you discontinue your use
of loadbalancer.jar in this release. Under high loads, loadbalancer.jar may not
function properly. For a true load balancing and high-availability solution,
please move to use OHS, OPMN, and mod_OC4J. For more information, please see
http://otn.oracle.com/products/ias/ohs/content.html
Balancer initialized...
what load balancer should i use for web clustering
<frontend host="balancer-host" port="balancer-port" />
balancer-host=localhost
balancer-port=80
for all nodes i mentioned same host and port in http-web-site.xml.Is it correct?
i completed all the steps and run http://localhost:6666/session/SessionServlet
i hit 3 times
in the different browser http://localhost:7777/session/SessionServlet
instead of coming 4 it starting from 1 only.

can i use this loadbalancer.jar or not?
how to mod_oc4j in standalone app server

Windows Event Collector - Built-in options for load balancing and high availability ?

Hello,
I have a working collector. config is source initiated, and pushed by GPO.
I would like to deploy a second collector for high availability and load balancing. What are the available options ? I have not found any guidance on TechNet articles.
As a low cost option, is it fine to simply start using DNS round-robin with a common alias for both servers pushed as a collector name through GPO ?
In my GPO Policy, if I individually declare both servers, events are forwarded twice, once for each server. Indeed it does cover high availability, but not really optimized.
Thanks for your help.

Hi,
>>As a low cost option, is it fine to simply start using DNS round-robin with a common alias for both servers pushed as a collector name through GPO ?
Based on the description, we can utilize DNS round robin to distribute workloads and increase fault tolerance. By default, DNS uses round robin to rotate the order of RR data returned in query answers where multiple RRs of the same type exist for a queried
DNS domain name. This feature provides a simple method for load balancing client use of Web servers and other frequently queried multihomed computers. Besides, by default, DNS will perform round-robin rotation for all RR types.
Regarding DNS round robin, the following article can be referred to for more information.
Configuring round robin
http://technet.microsoft.com/en-us/library/cc787484(v=ws.10).aspx
TechNet Subscriber Support
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Best regards,
Frank Shen

Tuxedo and High Availability

Can you provide some information on how Tuxedo can be configured in a high availability
environment. Specifically running Tux 7.1 on AIX 4.3 with HACMP/ES. I am planning
on running with a 'cascading N+1' configuration and have concerns over the ability
of the standby node to take over a failed node succesfully due to config dependancies
on the machine name. Is there a white paper detailing use of Tux in a high availability
environment ?

Found the answers and thought would share it.
1. Can load balancing be achieved in MP setup or is this a high availability configuration?
Both - MP supports load balancing and high availability 2. In an MP setup, can a workstation client continue to work even after the master node gets migrated? If so, can we have both (or all nodes and their WSL) listed in WSNADDR for this to happen
Correct.

Load Balancing and WLS primary server offset

I've got a load balancer in front of my WLS cluster, and I'm trying to
          set up load balancing based on WLS clustering. What I need to know to
          do this is the offset within the cookie that's responsible for
          determining which machine within the cluster to direct to.
          Any idea how I can get this information?
          thanks,
          cfraser


Chris Fraser wrote:
          > The proxy/plug-in solution sounds pretty cool, but I've got a high speed
          > Alteon Load Balancer already set up. I would prefer to use that as the load
          > balancer to the WL cluster rather than pay to bring another WLS online to do
          > pretty much what the load balancer, that I already own, can do. I know that
          > going this route means that we're probably not going to be able to do things
          > like failover to the secondary when the primary dies, but we will be able to
          > load balance and also have the ability to dynamically add/delete servers
          > from the list of available servers as they are brought up/down.
          In Memory session replication doesn't work without our plugins. I will have to
          do little bit of investigation to figure out if other persistence mechanism's
          would work without our plugins if you are interested in them. I have to remind
          you though that other types of persistence mechanism's we support are slower
          compared to in memory session replication.
          > Are there any plans to work with an Alteon or a Foundry to have their Load
          > Balancers act as the front end to a WLS cluster?
          Currently none. We are taking steps to make the plugin's and cluster more
          robust, we currently don't have any plans to work with other 3rd party vendors.
          > For us it would be ideal, because we wouldn't have to support another piece of
          > software, we would just
          > have to support the hardware based Alteon, which can handle thousands of
          > transactions per second.
          > I understand that the primary and secondary server information is available
          > in the sessionID, I'm just not quite sure how to extract it.
          This information is saved in the cookie. But I wouldn't count that, as we
          have plans to change this. I cannot give your more details.
          > Is there a particular offset within the session ID where it can always be
          > found?
          I don't quite get what you mean here.
          Hope this helps.
          - Prasad
          > thanks for the help,
          > cfraser
          > ----------
          > C h r i s t o p h e r A . F r a s e r
          > Director, Technology
          > macroplay.com, Inc.
          > [email protected]
          >
          > Viresh Garg wrote:
          >
          > > You should be using
          > > -- NES +NSAPI Plugin
          > > -- IIS + ISAPI Plugin
          > > -- WEblogic server acting as proxy
          > > -- Apache +Apache Plugin ( only in Denali)
          > >
          > > front-ending your Weblogic cluster
          > >
          > > These proxies/plug-ins are smart to do a lot of things like:
          > >
          > > -- Load balancing in weblogic cluster
          > > -- Adding/deleting servers dynamically in cluster when the servers
          > > join/leave Weblogic cluster
          > > -- failover to secondary when primary dies.
          > >
          > > As far as the information about primary and secondary is concerned it is
          > > available in session ID.
          > >
          > > --Viresh Garg
          > >
          > > Chris Fraser wrote:
          > >
          > > > I've got a load balancer in front of my WLS cluster, and I'm trying to
          > > > set up load balancing based on WLS clustering. What I need to know to
          > > > do this is the offset within the cookie that's responsible for
          > > > determining which machine within the cluster to direct to.
          > > >
          > > > Any idea how I can get this information?
          > > >
          > > > thanks,
          > > > cfraser

2 ISP load balancing and redundancy

Hello!!
Our small company has about 40 branches spreaded within city. Branches are connected by optic wire supplied by our ISP. So in ISP our branches are located in one VLAN. From every branch we created VPN tunnel to our server room in central office. Central office is like a cetner point. If optic wire fails to central office, there would no VPN tunnels and no network to all branches. Moreover, all the traffice goes through central office.
Now we decided to pave one more optic line to our central office. And that will increase bandwidth and redundancy.
Private network topology: There are no default gateways and ip-addresses. For examle, at first branch I will plug computer directly into media converter and at the second branch plug another computer to the media converter. After that this two computers became in one network. And can assign any ip addresses to them.
What I have: our firewall do enough work, don't want to overload it. But we have some free ports in our new cisco 3750. The question is how to do load balancing and redundanccy? Can it do load balancing according to traffic? And how load balance incoming traffic? For example, connection was established from branche's router, how this router will choose through which line make connection? By the way, at all branches we use noisy cisco
3700 series routers.

Sorry for upping 1 year old threat.
We talked to our Network Provider. They said "these two cables are coming from two different places, so there is no way to use etherchannel. You must use active-standby solution."
Relying on STP we just put two cables into 3750 stack. But with default STP settings, connection was very unstable, many packet losses and disconnections. So we found easy solution with "flex links", making one interface backup of the other. And only now I recognized that this is not a failover solution. Because, if network beyond media converter will down, link from media converter to switch would still up.
What could I do to make our L2 WAN redundant? Are there any additional STP settings.

Load balancing and Failover

Hello,
We are wondering how load-balancing and failover of tpcall() work with
WTC:
The scenario:
We have one WLS Domain and two Tuxedo Domains. The Tuxedo Domains offer
the same set of services.
In the bdmconfig.xml, we specify connection_policy as 'ON_STARTUP' for
both Remote Tuxedo Domains. We also Import (T_DM_IMPORT) the same
Tuxedo Service from both Tuxedo Domains.
Questions:
1. Is there any load-balancing of the tpcall between the two Domains? If
so, is it round-robin? If round-robin, what determines the order?
2. If it is ONLY Failover, what determines the order of the tpcall? And,
is the Failover automatic? Or do we need to code for retry on failure?
3. ON_DEMAND vs ON_STARTUP: Does ON_DEMAND drop the connection to the
remote domain upon tpterm? And does ON_STARTUP use a pool of
TuxedoConnection objects?
4. Are there any configuration parameters for
'max_number-of_connections? What determines how many simultaneous
connections can be made?
Thanks,
Suresh Mohan.

Hi Suresh,
The following are my answers to your questions.
Suresh Mohan wrote:
Hello,
We are wondering how load-balancing and failover of tpcall() work with
WTC:
The scenario:
We have one WLS Domain and two Tuxedo Domains. The Tuxedo Domains offer
the same set of services.
In the bdmconfig.xml, we specify connection_policy as 'ON_STARTUP' for
both Remote Tuxedo Domains. We also Import (T_DM_IMPORT) the same
Tuxedo Service from both Tuxedo Domains.
Questions:
1. Is there any load-balancing of the tpcall between the two Domains? If
so, is it round-robin? If round-robin, what determines the order?Yes there is a load balancing between two remote Tuxedo TDomain Gateways.
The algorithm is random, not RR. Over time this should give equal
opportunities to both remote TDomain.
>
2. If it is ONLY Failover, what determines the order of the tpcall? And,
is the Failover automatic? Or do we need to code for retry on failure?The load balancing is always there. The failover is automatic. When a
connection to a remote TDomain encountered a problem (ie network) the remote
domain will be put on retry open connection (in ON_STARTUP) and the load
balancing will not select it until the connection re-established.
However, the tpcall() that encountered the error will not be retried to send
to different destination. It is up to the application to decide whether it
want to resend. Any requests called after the error will not select the
failed Remote TDomain.
>
3. ON_DEMAND vs ON_STARTUP: Does ON_DEMAND drop the connection to the
remote domain upon tpterm? And does ON_STARTUP use a pool of
TuxedoConnection objects?TPTERM() only terminate your application session to WTC. WTC still maintain
a secured T-session to remote Tuxedo TDomain. WTC does not use a pool of
TuxedoConnection Objects, the object stored in the JNDI refers to WTC.
>
4. Are there any configuration parameters for
'max_number-of_connections? What determines how many simultaneous
connections can be made?No. As described in #3, there is no need to use connection pool in WTC. WTC
uses session and virtual circuit design concept as Tuxedo TDOMAIN, the
logical pool is created/destroyed dynamically. That is the reason why you
can have a lot of TPACALL() outstanding at the same time. (The limitation is
the availability system resource.)
>
>
Thanks,
Suresh Mohan.Regards,
Hong-Hsi :-)

Discussion on load-balance and load-sharing

Hi, I found a article, which discuss the difference between load-balance and load-sharing. I think the explanation is pretty good, please see below. But I still have a question: how can we decide to choose one the both balance in the production environment ? Thank you
"In short, load balancing tries to distribute traffic evenly over multiple paths, whereas, load sharing intends to do it (for the lack of a better term) equally. True load balancing is difficult to achieve. For example, let's say there were two links (100 mbps and 300 mpbs) and a router needed to send out 600 mbps of traffic. Load balancing would distribute the traffic evenly, sending 300 mbps on each link. On the contrary, load sharing would divide the traffic equally based on the available resources, sending 200 mbps on the slower link and 400 mbps on the faster one. "

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Posting
That's not how Cisco uses the terms, and generically they are often used almost interchangeably.
Cisco uses load balancing as the catch all for how a single L3 device routes across multiple paths to the same destination. Equal metrics or equal actual load distribution are not required. Most often, load balancing will be discussed with ECMP, but unequal path loading balancing will include Cisco's proprietary IGPs, such as EIGRP.
Cisco uses load sharing when using multiple paths when a single L3 devices doesn't normally route across multiple paths or multiple L3 devices are involved. Cisco load sharing discussions usually revolve around BGP.
Generically, I would say load balancing has more of a dynamic aspect to it, i.e. something is trying to actively balance traffic across multiple paths, while load sharing might mean multiple paths are utilized but not actively dynamically balanced.
I'm unsure what's your question with a production environment.

ISA570-Load balancing and Losing packets

I am load balancing two isp's. One isp is fine, but the other I have very high packet loss when pinging the corresponding wan interface from any machine located outside our network. During the packet loss, I cannot https to our firewall from outside our network, but I can rdp using a different address on that same isp and ping another machine located inside our network, it seems only the wan interface is having the issues. Our isp uses icmp to our wan interface and they started noticing the loss the other day, again the other isp loses no packets. I have no issues with clients losing connection from that isp so it looks like it is an issue from outside in only on that wan interface.
I have a spare ISA and that is experiencing no packet loss when using another ip from the problem isp on it's wan interface. The isa's have the same configuration and when I tried moving completely to the backup isa it continued with the same issue. Upgraded to a later firmware, still the same issue. I even took a laptop and put it on our switch that is before the isa and gave it a static public address and I can ping it with no problem from the outside. I can also ping from the laptop to the wan port of the prod isa that is losing packets and it replies as it should, which I assumed would lose packets if it were the isa having issues, but it didn't.
I know this has nothing to do with Cisco security services as on the backup firewall it was still losing packets when we moved the connections over to it.
I can ping from inside my network to the public wan address with no loss when outside machines are having problems.
I can ping the problem wan address from a laptop or from isa(IP = 64.x.x.42) to isa(IP = 64.x.x.45) with no packet loss.
This is a head scratcher and I need some real help here.

Never figured this one out. However, I was able to figure out how this starts. A couple of weeks ago we had an issue with an ISP and we disabled that interface during the day and re-enabled at the end of the day and thats when we noticed ICMP breaks to other ISP.. I don't know why but the ISP we renabled we can ping just fine, but the other one always has issues. The only fix is to enable link failover detection and both WAN interfaces become pingable again.
Now, we use load balancing and one issue we are experiencing is that randomly both WAN interfaces go down and I can confirm this with a ping utility we use off site that pings both WAN interfaces and also each ISP gateway they are connected to. When this happens the ISP's gateways are reachable and neither WAN interface on the ISA are. I am still on .15 version of the firmware, because there were too many issues with newer releases. Is this a known issue?

Load Balancing and NIC Teaming

Hi! i have been looking through lots of links and none of them actually can fully answer my queries.
I am to do a writeup on load balancing and NIC Teaming, is there any1 that knows what are the commonly used load balancing and NIC Teaming methods, when to use each method, and the advantages and disadvantages of each method and the configuration for each
method!
Sorry its lots of questions but i have to do a detailed writeup!
Many thanks in advance :D

HI
NIC Teaming - On a single server, you will have mutiple NIC. You can Team the NIC so that both NIC will act togather to provide better bandwidth and High avaliblity.
Example : NIC 1 - 1 GB and NIC -2 1 GB so in Team it can act a 2 GB single NIC, If one fails speed will be reduced but it will have HA
Loadbalancing : Two servers hosting same content:
Example : Microsoft.com can be hosted in two or even more servers and a loadbalancer will be used to split load to each server based of the current load and traffic.
No disadvantages

Load-balancing and fail-over between web containers and EJB containers

When web components and EJB components are run in different OC4J instances, can we achieve load-balancing and fail-over between web containers and EJB containers?
null

It looks like there is clustering, but not loadbalancing available for rmi
from the rmi.xml configuration. The application will treat any ejbs on the
cluster as one-to-one look-ups. Orion will go out and get the first ejb
available on the cluster. See the docs on configuring rmi.xml (and also the
note below).
That is a kind-of failover, because if machine A goes down, and the
myotherAejbs.jar are on machine B too, orion will go out and get the bean
from machine B when it can't find machine A. But it doesn't go machine A
then machine B for each remote instance of the bean. You could also specify
the maximum number of instances of a bean, and as one machine gets "loaded",
orion would go to the next available machine...but that's not really
loadbalancing.
That is, you can set up your web-apps with ejbs, but let all of the ejbs be
remote="true" in the orion-application.xml file:
<?xml version="1.0"?>
<!DOCTYPE orion-application PUBLIC "-//Evermind//DTD J2EE Application
runtime 1.2//EN" "http://www.orionserver.com/dtds/orion-application.dtd">
<orion-application deployment-version="1.5.2">
<ejb-module remote="true" path="myotherAejbs.jar" />
<ejb-module remote="true" path="myotherBejbs.jar" />
<ejb-module remote="true" path="myotherCejbs.jar" />
&ltweb-module id="mysite" path="mysite.war" />
... other stuff ...
</orion-application>In the rmi.xml you would define your clustering:
<cluster host="230.0.0.1" id="123" password="123abc" port="9127"
username="cluster-user" />
Tag that is defined if the application is to be clustered. Used to set up
a local multicast cluster. A username and password used for the servers to
intercommunicate also needs to be specified.
host - The multicast host/ip to transmit and receive cluster data on. The
default is 230.0.0.1.
id - The id (number) of this cluster node to identify itself with in the
cluster. The default is based on local machine IP.
password - The password configured for cluster access. Needs to match that
of the other nodes in the cluster.
port - The port to transmit and receive cluster data on. The default is
9127.
username - The username configured for cluster access. Needs to match that
of the other nodes in the cluster.

Load balancing and transparent failover in RAC 11g

Hi,
The only way to configure load balancing and transparent failover in RAC 11 g R2 is using the clauses LOAD_BALANCING and FAILOVER on the tnsnames.ora of application server. Is that correct?

If the database is admin-managed, I shall suggest that rather than playing with the remote_listener parameter , set one service as preferred for one instance.For the other service, let it be preferred on both the nodes. The service with just one instance as Preferred won't be able to use loab-balancing as there is just one instance available for its disposal.
HTH
Aman....

Network Load Balancing and failover for AFP Sharing

Dear all,
Somebody kindly teach me to use round robin DNS to perform the network load balancing, it's success but not the failover.
I have 4 xserve and want to do the load balancing and failover at the same time.
I have read the IP failover document and setup it successfully, but anyone know is it possible to do the IP failover for more than 2 server?
For example, 4 server serving the AFP service at the same time, maybe I have 1 more extra server to do the IP failover for thoese 4 servers.
As I know, IP failover require Firewire as the heartbeat detection. But one xserve only have 2 firewire ports. May I setting up the IP failover only by a ethernet port and an IP address? does it possible to detect and failover to any server after server down has been detected?
I believe load balancer maybe the best solution but its cost is too high.
Thanks any advance!
Karllee

well, u have 2 options here
software load balancing
request comes it foo.com -> ws7u2 hosting foo.com is configured to run as reverse proxy . this server sends any incoming requests to one of the four back end web server 7 handling your incoming request
hardware load balancing (this you need to invest)
request comes to hardware load balancer who responds for foo.com -> sends requests to four ws7 server hosting your application
you could try out how software load balancing works out for you before you invest in hardware load balancing
here is more instruction on configuring ws7 + reverse proxy (software load configuration)
- install ws7 on foo.com
- create a new configuration (choose port 80, disable java

LRT224 Load Balancing and Link Failover

Hi, I am new to this forum. I have recently set up the LRT224 with two different ISP's. I am having problems configuring the Load Balance and Link Failover.
When I have Load Balance selected only one ISP (WAN 1) is active, the other (WAN2, ISP modem) remains inactive. Why is Load Balance only engaging one ISP?
When I have Link Failover selected, even with attempts and seconds configured to one second, and WAN1 has packets lost, it doesn't switch over to WAN2.
I am not tech savey but any help will be greatly appreciated so that I can get both ISP's active with Load Balance or at least have Link Failover work almost instantly. Thanks.

Hi @BSue2015,
If both WAN1 and WAN2 are already getting IP Addresses from your ISPs then we can say that Load Balance is working. To check it further, do a speed test by going to http://www.speedtest.net. Dual WAN connections are doubling the amount of available full speed connections due to the load balancing. The speed should have its maximum throughput even if you have several users on the network.

One of 4 node RAC always have higher load averages and higher than others

Hello,
We have a 4 node rac, 9208 on linux 4. When viewing top, we noticed the same one node always have a higher load average than the other 3 nodes. Is this normal. Loan balance is working fine but this one node always have higher load average. This is the node where we do the rac installation. Thank you.

I do not remember what is the default for clb_goal (client load balancing) for 9i but 10g is LONG.
check it
select clb_goal from dba_services where name = <service name>
you may have to change from LONG to SHORT OR SHORT to LONG depending your connection types.
dbms_service.MODIFY_SERVICE(‘<service>’,clb_goal=> dbms_service.CLB_GOAL_LONG);
Read the following article.
http://www.databasejournal.com/features/oracle/article.php/3659411/Oracle-RAC-Administration---Part-15-Connection-Load-Balancing-and-FAN.htm

Load balancing and High Availability topology

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