Load balancing vs Replication

          Supposedly simple question:
          if you loadbalance your HTTP requests between 3 servers in a cluster serv1,serv2,serv3 and WL cluster creates primary state on serv1 and replicates to secondary serv2.
          What happens when balancer routes the next request to serv3?

Yes that is correct. Weblogic is guilty of pre-meditated load balancing,
          and never acts on impulse.
          Peace,
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com
          +1.617.623.5782
          WebLogic Consulting Available
          "Gennady Shapiro" <[email protected]> wrote in message
          news:[email protected]...
          >
          > Wei,
          >
          > so if HTTP requests are always routed to their primary(secondary) servers
          then where is load balancing?
          > If I understand correctly, ISAPI proxy (f.e.) does rather session
          balancing than true HTTP hit balancing. Is this correct?
          >
          >
          > Thank you much.
          >
          >
          > "Wei Guan" <[email protected]> wrote:
          > >In your case, serv1 is the primary and serv2 is the secondary. Both IPs
          are
          > >encoded in cookie or via URL rewriting. Plugins or WebLogic HTTP
          > >ClusterServlet will decode this informaiton and always routing the
          > >following HTTP request to primary or secondary if primary failed.
          > >
          > >Hope it clears some cloud.
          > >
          > >--
          > >
          > >Cheers - Wei
          > >
          > >
          > >"Gennady Shapiro" <[email protected]> wrote in message
          > >news:[email protected]...
          > >>
          > >> Supposedly simple question:
          > >> if you loadbalance your HTTP requests between 3 servers in a cluster
          > >serv1,serv2,serv3 and WL cluster creates primary state on serv1 and
          > >replicates to secondary serv2.
          > >> What happens when balancer routes the next request to serv3?
          > >>
          > >>
          > >
          > >
          >

Similar Messages

Load balance about replication

Hi,
Thank you in advance!
If I have configured replication between two directory server, a master and a consumer,
can this replication provide load balance? If the master has lots of access or it has problems,
can it redirect to the consumer automatically ?
Thanks ahead!

No, directory server replication doesn't give you load balancing or failover. If that's what you're after you'll need a load balancer, or consider Sun's Directory Proxy server.
[http://docs.sun.com/app/docs/doc/820-2763/figvo]

Questions on replication and h/w load balancer

          Why does h/w load balancer have to support passive cookies and inspect them to
          dispatch the request to the primary server first? If we have in-memory replication
          and if h/w loadbalancer just dispatches the http request from the client to any
          of the weblogic servers in the cluster wouldnt this work?
          Is it to pin the session to the creator server to minimize the chance of replication
          misses due to n/w issues, member server slow speed, buffer overwrite etc.
          -Shiraz


Yes, and previous to 6.1 (?) if the request showed up at the wrong server it
          would fail.
          Peace,
          Cameron Purdy
          Tangosol Inc.
          Tangosol Coherence: Clustered Coherent Cache for J2EE
          Information at http://www.tangosol.com/
          "Shiraz Zaidi" <[email protected]> wrote in message
          news:3c15aa10$[email protected]..
          >
          > Why does h/w load balancer have to support passive cookies and inspect
          them to
          > dispatch the request to the primary server first? If we have in-memory
          replication
          > and if h/w loadbalancer just dispatches the http request from the client
          to any
          > of the weblogic servers in the cluster wouldnt this work?
          >
          > Is it to pin the session to the creator server to minimize the chance of
          replication
          > misses due to n/w issues, member server slow speed, buffer overwrite etc.
          >
          > -Shiraz

Load Balancing and Asynchronous Multimaster Replication

We are planning a new project with 2 server lines for load balancing reasons. We also plan to use sessions being valid for 30 minutes. Each of the 2 server lines has its own Oracle database (identical tables) for the transactions. Within one session the load balancing sends the user always to the same server line.
Independant transactions are executed on both server lines.
Is Asynchronous Multimaster Replication the adequate solution to have the two databases synchronized, what has to be considered (network, memory, cpu) or what else can (has to) be used ?
We want to avoid a RAC solution because of the high costs.

The two options that come to mind here are asynchronous multimaster replication and Oracle Streams.
- What version of the Oracle database will you be using?
- What sort of transaction volume do you anticipate? How much redo generation?
- What sort of connection exists between the two machines?
- Is there an upper limit on the time that can be taken to replicate a transaction from one machine to the other?
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

3rd party distributed SW load balancing with In-Memory Replication

          Hi,
          Could someone please comment on the feasibility of the following setup?
          I've started testing replication with a software load balancing product. This
          product lets all nodes receive all packets and uses a kernel-level filter
          to let only one node at the time receive it. Since there's minimum 1 heartbeat
          between the nodes, there are several NICs in each node.
          At the moment it seems like it doesn't work: - I use the SessionServlet - with
          a 2-node cluster I first have the 2 nodes up and I access it with a single client:
          .the LB is configured to be sticky wrt. source IP address, so the same node gets
          all the traffic - when I stop the node receiving the traffic the other node takes
          over (I changed the colours of SessionServlet) . however, the counter restarts
          at zero
          From what I read of the in-memory replication documentation I thought that it
          might work also with a distributed software load balancing cluster. Any comments
          on the feasability of this?
          Is there a way to debug replication (in WLS6SP1)? I don't see any replication
          messages in the logs, so I'm not even sure that it works at all. - I do get a
          message about "Clustering Services startting" when I start the examples server
          on each node - is there anything tto look for in the console to make sure that
          things are working? - the evaluation license for WLS6SP1 on NT seems to support
          In-Memory Replication and Cluster. However, I've also seen a Cluster-II somewhere:
          is that needed?
          Thanks for your attention!
          Regards, Frank Olsen


We are considering Resonate as one of the software load balancer. We haven't certified
          them yet. I have no idea how long its going to take.
          As a base rule if the SWLB can do the load balancing and maintain stickyness that is fine
          with us as long as it doesn't modify the cookie or the URL if URL rewriting is enabled.
          Having said that if you run into problems we won't be able to support you since it is not
          certified.
          -- Prasad
          Frank Olsen wrote:
          > Prasad Peddada <[email protected]> wrote:
          > >Frank Olsen wrote:
          > >
          > >> Hi,
          > >>
          > > We don't support any 3rd party software load balancers.
          >
          > Does that mean that there are technical reasones why it won't work, or just that
          > you haven't tested it?
          >
          > > As >I said before I am thinking your configuration is >incorrect if n-memory
          > replication is not working. I would >strongly suggest you look at webapp deployment
          > descriptor and >then the config.xml file.
          >
          > OK.
          >
          > >Also doing sticky based on source ip address is not good. You >should do it based
          > on passive cookie persistence or active >cookie persistence (with cookie insert,
          > a new one).
          > >
          >
          > I agree that various source-based sticky options (IP, port; network) are not the
          > best solution. In our current implementation we can't do this because the SW load
          > balancer is based on filtering IP packets on the driver level.
          >
          > Currently I'm more interested in understanding whether it can our SW load balancer
          > can work with your replication at all?
          >
          > What makes me think that it could work is that in WLS6.0 a session failed over
          > to any cluster node can recover the replicated session.
          >
          > Can there be a problem with the cookies?
          > - are the P/S for replication put in the cookie by the node itself or by the proxy/HW
          > load balancer?
          >
          > >
          > >The options are -Dweblogic.debug.DebugReplication=true and
          > >-Dweblogic.debug.DebugReplicationDetails=true
          > >
          >
          > Great, thanks!
          >
          > Regards,
          > Frank Olsen

Session replication in oc4j load balancing not working ..

Hi All,
I have windows 2000 machine. I have installed 2 instances of oc4j running on ports 8888 and 8889. I started the loadbalancer.jar in the first instance, started the first oc4j instance and then started the second oc4j instance. I have a common application deployed on both instance1 and instance2 and that is nothing but out famous SessionServlet.
If I access this servlet using http://localhost:80/app/servlet/SessionServlet then I am getting a count as 1 . My loadbalancer that is started from first oc4j instance(running on port 8888) is showing that the request is routed to the first instance. I stopped my first instance1 and then again from the same browser/session/client if I access the same servlet using http://localhost:80/app/servlet/SessionServlet then still I am seeing the count as 1 instead of 2 . At this point my loadbalancer is showing that the request is routed to the second oc4j instance(running on port 8889) since first instance is stopped. So why am I seeing the count as 1 instead as 2.
Also,
1. Is it enough that we start the loadbalancer.jar in the first oc4j instance. What about the loadbalancer.jar in the second oc4j instance ?
2. We all know that Apache HTTP Server runs on port 80. But since I didnt[i]Long postings are being truncated to ~1 kB at this time.

thank you debu, I have one doubt . In the clustering/load-balancing documentation at metalink(doc id: 151717.1) it is said that in point 4b that we should add the tag <cluster-config /> to orion-web.xml file but this file will be created only after the web application is deployed and it is accessed atlest for one time. So is it that we should first deploy the web application and then access it for atlest one time then stop the server and add this tag .. or is there any other way workaround ?

ISE 1.2 - Multiple NICs/Load Balancing for DHCP Probe

Hello guys
Just prepping an ISE 1.2 patch 8 setup in our organization. I am going for the virtual appliances with multiple NICs. It will be a distributed deployment with 4 x PSNs behind a load balancer and there is no requirement for wireless or guest user at the moment. I've got 2 points I will like to get some guidance on:
Our DC has a dedicated mgmt network and I plan to IP the gig0 interface of the PANs, MNTs and PSNs from this subnet. All device admin, clustering, config replication, etc will be over this interface. However, RADIUS/probe/other user traffic to the ISE PSNs will be over the gig1 interface which will be addressed from another L3 network. Is this a supported configuration in ISE?
I intend to use the DHCP probe as part of device profiling and will ideally like to have just an additional ip helper to add to our switch SVI config. Also, it will appear that WLCs can only be configured for 2 DHCP servers for a given network so another consideration for when we bringing our WLAN in scope. We however use ACE load balancers within our DC and from what I have read, they do not support DHCP load balancing. Are there any workarounds to using the DHCP probe with multiple PSNs without having to add each node as an ip helper/DHCP server on the NADs?
Thanks in advance
Sayre

Hello Sayre-
For Question #1:
Management is restricted to GigabitEthernet 0 and that cannot be changed so you should be good there
You can configure Radius and Profiling to be enabled on other interfaces
Even though you are not using guest services yet, you can dedicate an interface just for that. As a result, you can separate guest traffic completely from your production network
Take a look at this link for more info:
http://www.cisco.com/c/en/us/td/docs/security/ise/1-2/installation_guide/ise_ig/ise_app_c-ports.html
For Question #2
If you are using a Cisco WLC and running code 7.4 and newer you don't need to mess with the IP helper configurations.
The controller can be configured to act as a collector for client profiling and interact with the DHCP thread along with the RADIUS accounting task that is running on the controller. The controller receives a copy of the DHCP request packet sent from the DHCP thread and parses the DHCP packet for two options:
–Option 12—HostName of the client
–Option 60—The Vendor Class Identifier
After this information is gathered from the DHCP_REQUEST packet, a message is formed by the controller with these option fields and is sent to the RADIUS accounting thread, which is in turn transmitted to the ISE in the form of an interim accounting message.
Both DHCP and HTTP profiling settings are located under the "Advanced" configuration tab in the WLC
On the other hand, you can also use Anycast for profiling. You can check out some of Cisco Live's sessions for more info on that. Here is one that is from a couple of years (There are more recent ones that are available as well):
http://www.alcatron.net/Cisco%20Live%202013%20Melbourne/Cisco%20Live%20Content/Security/BRKSEC-3040%20%20Advanced%20ISE%20and%20Secure%20Access%20Deployment.pdf
I hope this helps!
Thank you for rating helpful posts!

ISE 1.2 and load balancing...

I'm looking into configuring load balancing behind F5's. I know this can be done and have read the documentation on what is required. I still have a couple of questions about it:
1. When you load balance the RADIUS traffic do you have to create separate VIP's for the auth and accounting ports (1812 & 1813)?
2. Are there good configuration examples out there for VIP Configs and setting up the VIP's to run in routed mode?
3. Are there any caveats or lessons learned that other people have experienced besides what is documented?
Thanks.

jgroup is how db sync/ replication work in 1.2, which replace the queuing mechnism in 1.1.
but this should not be related to PSN LB? do you mean you want to lb requests between several PSNs?
using F5 or ACE can help, also 1.2 support wildcard certificate will help address the cert warning problem.
Sent from Cisco Technical Support iPad App

Load Balancing Directory Servers with Access Manager - Simple questions

Hi.
We are in the process of configuring 2 Access Manager instances (servers) accessing the same logical LDAP repository (comprising physically of two Directory Servers working together with Multi-Master Replication configured and tested) For doing this, we are following guide number 819-6258.
The guide uses BigIP load balancer for load balancing the directory servers. However, we intend to use Directory Proxy Server. Since we faced some (unresolved) issues last time that we used DPS, there are some simple questions that I would be very grateful to have answers to:
1. The guide, in section 3.2.10 (To configure Access Manager 1 with the Directory Server load balancer), talks about making changes at 4 places, and replacing the existing entry (hostname and port) with the load balancer's hostname and port (assuming that the load balancer has already been configured). It says that changes need not be made on Access Manager 2 since the LDAPs are in replication, and hence changes will be replicated at all places. However, the guide also states that changes have to be made in two files, namely AMConfig.properties, and the serverconfig.xml file. But these changes will not be reflected on Access Manager 2, since these files are local on each machine.
Question 1. Do changes have to be made in AMConfig.properties and serverconfig.xml files on the other machine hosting Access Manager 2?
Question 2: What is the purpose of putting these values here? Specifically, what is achieved by specifying the Directory server host and port in AMConfig.properties, as well as in serverconfig.xml?
Question 3. In the HTTP console, there is the option of specifying multiple primary LDAP servers, as well as multiple secondary LDAP servers. What is the purpose of these? Are secondary servers attempted when none of the list in the primary list are accessible? Also, if there are multiple entries in the primary server list, are they accessed in a round robin fashion (hereby providing rudimentary load balancing), or are other servers accessed only when the one mentioned first is not reachable etc.?
2. Since I do not have a load balancer setup yet, I tried the following deviation to the above, which, according to me, should have worked. If viewed in the HTTP console, LDAP / Membership / MSISDN and Policy configuration all pointed to the DS on host 1. When I changed all these to point to the directory server on host 2 (and made AMConfig.properties and serverconfig.xml on host 1 point to DS of host 2 as well), things should have worked fine, but apparently Access manager 1 could not be started. Error from Webserver:
[14/Aug/2006:04:30:36] info (13937): WEB0100: Loading web module in virtual server [https-machine_1_FQDN] at [search]
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: Exception in thread "EventService" java.lang.ExceptionInInitializerError
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: at com.iplanet.services.ldap.event.EventServicePolling.run(EventServicePolling.java:132)
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: at java.lang.Thread.run(Thread.java:595)
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: Caused by: java.lang.InterruptedException
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: at com.sun.identity.sm.ServiceManager.<clinit>(ServiceManager.java:74)
[14/Aug/2006:04:31:48] warning (13937): CORE3283: stderr: ... 2 more
In effect, AM on 1 did not start. On rolling back the changes, things again worked like previously.
Will be really grateful for any help / insight / experience on dealing with the above.
Thanks!

Update to the above, incase anyone is reading:
We setup a similar setup in Windows, and it worked. Here is a detailed account of what was done:
1. Host 1: Start installer, install automatically, chose Directory server, Directory Administration server, Directory Proxy server, Web server, Access Manager.
All installed, and worked fine. (AMConfig.properties, serverconfig.xml, and the info in LDAP service, all pointed to HOST1:389)
2. Host 2: Start installer, install automatically, chose Directory server, Directory Administration server, Directory Proxy server, Web server, Access Manager.
All installed, and worked fine. (AMConfig.properties, serverconfig.xml, and the info in LDAP service, all pointed to HOST2:389)
3. Host 1: Started replication. Set to Master
4. Host 2: Started replication. Set to Master
5. Host 1: Setup replication agreement to Host 2
6. Host 2: Setup replication agreement to Host 1
7. Initiated the remote replica from Host 1 ----> Host 2
Note that since default installation uses abc.....xyz as the encryption key, setting this to same was not an issue.
9. Started webserver for Host 1 and logged into AM as amadmin.
10. Added Host 2 FQDN in DNS Aliases / Realms
11. Added http://HOST2_FQDN:80 in the Platform server (instance) list.
12. Started Host 2 webserver. Logged in AM on Host 2, things worked fine.
At this stage, note the following:
a) Host 1:
AMConfig.properties file has
com.iplanet.am.directory.host=host1_FQDN
and
com.iplanet.am.directory.port=389
serverconfig.xml has:
<Server name="Server1" host="host1_FQDN" port="389" type="SIMPLE" />
b) Host 2:
AMConfig.properties file has
com.iplanet.am.directory.host=host2_FQDN
and
com.iplanet.am.directory.port=389
serverconfig.xml has:
<Server name="Server1" host="host2_FQDN" port="389" type="SIMPLE" />
c) If one logs into AM, and checks LDAP servers for LDAP / Policy Configuration / Membership etc services, they all contain Host2_FQDN:389 (which makes sense, since replica 2 was initialized from 1)
Returning back to the configuations:
13. On Host 1, login into the Admin server console of the Directory server. Navigate to the DPS, and confgure the following:
a) Network Group
b) LDAP servers
c) Load Balancing
d) Change Group
e) Action on-bind
f) Allow all actions (permit modification / deletion etc.).
g) any other configuations required - Am willing to give detailed steps if someone needs them to help me / themselves! :)
So now, we have DPS configured and running on Host1:489, and distributing load to DS1 and DS2 on a 50:50 basis.
14. Now, log into AM on Host 1, and instead of Host1_fqdn:389 (for DS) in the following places, specify Host1_fqdn:489 (for the DPS)--
LDAP Authentication
MSISDN server
Membership Service
Policy configuation.
Verified that this propagated to the Policy Configuration service and the LDAP authentication service that are already registered with the default organization.
15. Log out of AM. Following the documentation, modify directory.host and directory.port in AMConfig.properties to point to Host 1_FQDN and 489 respectively. Make this change in AMConfig.properties of both Host 1 as well as 2.
16. Edit serverconfig.xml on both hosts, and instead of they pointing to their local directory servers, point both to host1_FQDN:489
17. When you start the webserver, it will refuse to start. Will spew errors such as:
[https-host1_FQDN]: Sun ONE Web Server 6.1SP5 B06/23/2005 17:36
[https-host1_FQDN]: info: CORE3016: daemon is running as super-user
[https-host1_FQDN]: info: CORE5076: Using [Java HotSpot(TM) Server VM, Version 1.5.0_04] from [Sun Microsystems Inc.]
[https-host1_FQDN]: info: WEB0100: Loading web module in virtual server [https-host1_FQDN] at [amserver]
[https-host1_FQDN]: warning: WEB6100: locale-charset-info is deprecated, please use parameter-encoding
[https-host1_FQDN]: info: WEB0100: Loading web module in virtual server [https-host1_FQDN] at [ampassword]
[https-host1_FQDN]: warning: WEB6100: locale-charset-info is deprecated, please use parameter-encoding
[https-host1_FQDN]: info: WEB0100: Loading web module in virtual server [https-host1_FQDN] at [amcommon]
[https-host1_FQDN]: info: WEB0100: Loading web module in virtual server [https-host1_FQDN] at [amconsole]
[https-host1_FQDN]: warning: WEB6100: locale-charset-info is deprecated, please use parameter-encoding
[https-host1_FQDN]: info: WEB0100: Loading web module in virtual server [https-host1_FQDN] at [search]
[https-host1_FQDN]: warning: CORE3283: stderr: netscape.ldap.LDAPException: error result (32); matchedDN = dc=sun,dc=com; No such object (DN changed)
[https-host1_FQDN]: warning: CORE3283: stderr: Got LDAPServiceException code=-1
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.services.ldap.DSConfigMgr.getConnection(DSConfigMgr.java:357)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.services.ldap.DSConfigMgr.getNewFailoverConnection(DSConfigMgr.java:314)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.services.ldap.DSConfigMgr.getNewConnection(DSConfigMgr.java:253)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.services.ldap.DSConfigMgr.getNewProxyConnection(DSConfigMgr.java:184)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.services.ldap.DSConfigMgr.getNewProxyConnection(DSConfigMgr.java:194)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ums.DataLayer.initLdapPool(DataLayer.java:1248)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ums.DataLayer.(DataLayer.java:190)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ums.DataLayer.getInstance(DataLayer.java:215)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ums.DataLayer.getInstance(DataLayer.java:246)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.sun.identity.sm.ldap.SMSLdapObject.initialize(SMSLdapObject.java:156)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.sun.identity.sm.ldap.SMSLdapObject.(SMSLdapObject.java:124)
[https-host1_FQDN]: warning: CORE3283: stderr: at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
[https-host1_FQDN]: warning: CORE3283: stderr: at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
[https-host1_FQDN]: warning: CORE3283: stderr: at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
[https-host1_FQDN]: warning: CORE3283: stderr: at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
[https-host1_FQDN]: warning: CORE3283: stderr: at java.lang.Class.newInstance0(Class.java:350)
[https-host1_FQDN]: warning: CORE3283: stderr: at java.lang.Class.newInstance(Class.java:303)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.sun.identity.sm.SMSEntry.(SMSEntry.java:216)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.sun.identity.sm.ServiceSchemaManager.(ServiceSchemaManager.java:67)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.am.util.AMClientDetector.getServiceSchemaManager(AMClientDetector.java:219)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.am.util.AMClientDetector.(AMClientDetector.java:94)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.sun.mobile.filter.AMLController.init(AMLController.java:85)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:262)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:322)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.ApplicationFilterConfig.(ApplicationFilterConfig.java:120)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3271)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.StandardContext.start(StandardContext.java:3747)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ias.web.WebModule.start(WebModule.java:251)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.StandardHost.start(StandardHost.java:652)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:355)
[https-host1_FQDN]: warning: CORE3283: stderr: at org.apache.catalina.startup.Embedded.start(Embedded.java:995)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ias.web.WebContainer.start(WebContainer.java:431)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ias.web.WebContainer.startInstance(WebContainer.java:500)
[https-host1_FQDN]: warning: CORE3283: stderr: at com.iplanet.ias.server.J2EERunner.confPostInit(J2EERunner.java:161)
[https-host1_FQDN]: failure: WebModule[amserver]: WEB2783: Servlet /amserver threw load() exception
[https-host1_FQDN]: javax.servlet.ServletException: WEB2778: Servlet.init() for servlet LoginLogoutMapping threw exception
[https-host1_FQDN]: at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:949)
[https-host1_FQDN]: at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:813)
[https-host1_FQDN]: at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3478)
[https-host1_FQDN]: at org.apache.catalina.core.StandardContext.start(StandardContext.java:3760)
[https-host1_FQDN]: at com.iplanet.ias.web.WebModule.start(WebModule.java:251)
[https-host1_FQDN]: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: at org.apache.catalina.core.StandardHost.start(StandardHost.java:652)
[https-host1_FQDN]: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:355)
[https-host1_FQDN]: at org.apache.catalina.startup.Embedded.start(Embedded.java:995)
[https-host1_FQDN]: at com.iplanet.ias.web.WebContainer.start(WebContainer.java:431)
[https-host1_FQDN]: at com.iplanet.ias.web.WebContainer.startInstance(WebContainer.java:500)
[https-host1_FQDN]: at com.iplanet.ias.server.J2EERunner.confPostInit(J2EERunner.java:161)
[https-host1_FQDN]: ----- Root Cause -----
[https-host1_FQDN]: java.lang.NullPointerException
[https-host1_FQDN]: at com.sun.identity.authentication.UI.LoginLogoutMapping.init(LoginLogoutMapping.java:71)
[https-host1_FQDN]: at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:921)
[https-host1_FQDN]: at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:813)
[https-host1_FQDN]: at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3478)
[https-host1_FQDN]: at org.apache.catalina.core.StandardContext.start(StandardContext.java:3760)
[https-host1_FQDN]: at com.iplanet.ias.web.WebModule.start(WebModule.java:251)
[https-host1_FQDN]: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: at org.apache.catalina.core.StandardHost.start(StandardHost.java:652)
[https-host1_FQDN]: at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1133)
[https-host1_FQDN]: at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:355)
[https-host1_FQDN]: at org.apache.catalina.startup.Embedded.start(Embedded.java:995)
[https-host1_FQDN]: at com.iplanet.ias.web.WebContainer.start(WebContainer.java:431)
[https-host1_FQDN]: at com.iplanet.ias.web.WebContainer.startInstance(WebContainer.java:500)
[https-host1_FQDN]: at com.iplanet.ias.server.J2EERunner.confPostInit(J2EERunner.java:161)
[https-host1_FQDN]:
[https-host1_FQDN]: info: HTTP3072: [LS ls1] http://host1_FQDN:58080 [i]ready to accept requests
[https-host1_FQDN]: startup: server started successfully
Success!
The server https-host1_FQDN has started up.
The server infact, didn't start up (nothing even listening on 58080).
However, if AMConfig.properties is left as it originally was, and only serverconfig.xml files were changed as mentioned above, web servers started fine, and things worked all okay. (Alright, except for some glitches when viewed in /amconsole. If /amserver/console is accessed, all is good. Can this mean that all is still not well? I am not sure).
So far so good. Now comes the sad part. When the same is done on Solaris 9, things dont work. You continue to get the above error, OR the following error, and the web server will refuse to start:
Differences in Solaris and Windows are as follows:
1. Windows hosts have 1 IP and hostname. Solaris hosts have 3 IPs and hostnames (for DS, DPS, and webserver).
No other difference from an architectural perspective.
Any help / insight on why the above is not working (and why the hell does the documentation seem so sketchy / insecure / incorrect).
Thanks a bunch!

Load balancing problem

We need a load balancing setup that share the load for many web applications on multiple backend servers, but we don’t want the web apps to be activated on all backend servers at the same time. We want to configure all apps as “lazy” on all backend servers. They will then be activated when the first request to their DNS is made. Then the app is started on that backend server.
We have hundreds of apps and each backend server will become very slow if all apps are activated on all backend servers. The preferred solution would therefore be to not call all DNS names on all backend servers but to share the balance based on the DNS name in the requests. Sticky-session or sticky source-IP won’t be enough to solve this as they only stick to each user session.
If User-A request www.siteA.com he may be redirected to backend server 1 and then be kept there. But if User-B then requests the same www.siteA.com he may be redirected to backend server 2 and then be kept there. This means that the web application for siteA will be activated and loaded in both the backend servers. When we host hundreds of sites this will be a problem. We may have hundreds of backend servers but they will all end up loading all web apps over time and get out of memory.
The theory to get this work is a load balancer with the following logic:
1.     A request for a certain DNS comes in. For example: www.siteA.com
2.     Load balancer checks if this certain DNS has been redirected to a certain backend server before and if this server is alive
2.1.     (If not redirected before): Redirect the request to the backend server with least load. Store the selected backend route based on the DNS name.
2.2.     (If redirected before): Redirect the request to the assigned backend server for siteA.
3.     If a backend server is down then all DNS requests to this server will be redirected to another backend server with least load. All requests to these DNS names will be assigned to this backend server instead.
h3. Example of set up
Many DNS to one IP
192.168.1.1 www.siteA.com
192.168.1.1 www.siteB.com
192.168.1.1 www.siteC.com
Frontend load balancer
192.168.1.1 (load balancer)
Backend app servers
192.168.2.2 (App server 1)
192.168.2.3 (App server 2)
192.168.2.4 (App server 3)
h3. Snapshot of servers during load
App server 1
www.siteA.com (Activated)
www.siteB.com (Lazy)
www.siteC.com (Lazy)
App server 2
www.siteA.com (Lazy)
www.siteB.com (Activated)
www.siteC.com (Lazy)
App server 3
www.siteA.com (Lazy)
www.siteB.com (Lazy)
www.siteC.com (Activated)

Only from load balancing point of view cluster is not really needed.
apart from session replication and failover capabilities, few more benefits are there with clustering only if you are using a web server also.
Stuck threads can be due to lot's of problems like application issues, load issues etc, So first make sure you are getting stuck thread on both servers or only on one, if on one, then in this case your load balancing not working properly and sending more load to that server, and if you are getting stuck threads on both then try to add one more managed server.
Regards
Mukesh Negi
http://weblogicserveradministration.blogspot.com

Load Balancing Windows File Share? Doable ??

So I have a storage design question. The goal of this question is to find out how to best design a high availability storage solution without a single point of failure (SPF).
We need a storage location that needs to be accessed via an smb share in format of \\servername\sharename. We need to have an extremely high available solution as this share will be used to host remote IIS files and other important files being used by multiple
web servers. The most ideal solution is if there is a way to load balance an SMB fileshare so that it can be accessed by \\loadbalanced_name\sharename.
I am not sure if such technology exists for Windows 2008, Windows Storage Server, or with using 3rd party load balancing / file server / iscsi solution.
The current setup of our high available fileshare is with using Windows Clustering with 2 file servers attached to a singled Direct Attached Storage (DAS). Although we never really have an issue with this design, we would like to entirely eliminate the single
point of failure of the DAS.
So, any ideas / Input from anyone?
Thanks in advance!
Ed

In message
<[email protected]> ed
4t wowrack.com was claimed to have wrote:
hmm after thinking about this a little bit more, I guess I can use DFS.
However, I used to run a corporate file server for mid size company of 400 people using windows 2003 and I hated the replication to the guts. It doesn't seem to work well for large volumes...
FRS had issues, especially with large volumes. DFS-R solves that.
More importantly, DFS and DFS-R can be used independently, so if you
can't figure out how to get DFS-R working for you, you can always look
into your own replication scheme and just use DFS to get clients to the
appropriate server.

Apache plug-in won't load balance requests evenly on cluster

I can't seem to get the Apache plug-in to actually do round-robin load balancing
of HTTP
requests. It does random-robin, as I like to call it, since the plug-in will usually
hit all the
servers in the cluster but in a random fashion.
I've got three managed servers:
192.168.1.5:8001 (WL6 on Linux) 192.168.1.2:8001 (WL6 on Linux) 192.168.1.7:8001
(WL6 on Linux)
Admin server on 192.168.1.7:7000 (WL6 on W2k)
My Apache server is 1.3.9 (RedHat SSL) on 192.168.1.52.
The log file for each servers has something like this:
####<Apr 19, 2001 1:18:54 AM MDT> <Info> <Cluster> <neptune> <cluster1server1>
<main> <system> <> <000102> <Joined cluster cluster1 at address 225.0.0.5 on port
8001>
####<Apr 19, 2001 1:19:31 AM MDT> <Info> <Cluster> <neptune> <cluster1server1>
<ExecuteThread: '9' for queue: 'default'> <> <> <000127> <Adding
3773576126129840579S:192.168.1.2:[8001,8001,7002,7002,8001,7002,-1]:192.168.1.52
to the cluster> ####<Apr 19, 2001 1:19:31 AM MDT> <Info> <Cluster> <neptune>
<cluster1server1> <ExecuteThread: '11' for queue: 'default'> <> <> <000127> <Adding
-6393447100509727955S:192.168.1.5:[8001,8001,7002,7002,8001,7002,-1]:192.168.1.52
to the cluster>
So I believe I have correctly created a cluster, although I did not bother to
assign
replication groups for HTTP session replication (yet).
The Apache debug output indicates it knows about all three servers and I can see
it
doing the "random-robin" load balancing. Here is the output:
Thu Apr 19 00:20:53 2001 Initializing lastIndex=2 for a list of length=3 Thu Apr
19
00:20:53 2001 Init Srvr# [1] = [192.168.1.2:8001] load=1077584792 isGood=1077590272
numSk ip=134940256 Thu Apr 19 00:20:53 2001 Init Srvr# [2] = [192.168.1.5:8001]
load=1077584792 isGood=1077590272 numSk ip=134940256 Thu Apr 19 00:20:53 2001
Init Srvr# [3] = [192.168.1.7:8001] load=1077584792 isGood=1077590272 numSk
ip=134940256 Thu Apr 19 00:20:53 2001 INFO: SSL is not configured Thu Apr 19
00:20:53 2001 Now trying whatever is on the list; ci->canUseSrvrList = 1 Thu Apr
19
00:20:53 2001 INFO: New NON-SSL URL Thu Apr 19 00:20:53 2001 general list: trying
connect to '192.168.1.7'/8001 Thu Apr 19 00:20:53 2001 Connected to 192.168.1.7:8001
Thu Apr 19 00:20:53 2001 INFO: sysSend 320 Thu Apr 19 00:20:53 2001 INFO:
Reader::fill(): first=0 last=0 toRead=4096 Thu Apr 19 00:21:06 2001 parsed all
headers
OK Thu Apr 19 00:21:06 2001 Initializing lastIndex=1 for a list of length=3 Thu
Apr 19
00:21:06 2001 ###Response### : Srvr# [1] = [192.168.1.5:8001] load=1077584792
isGood=1077 546628 numSkip=1077546628 Thu Apr 19 00:21:06 2001 ###Response###
: Srvr# [2] = [192.168.1.2:8001] load=1077584792 isGood=1077 546628
numSkip=1077546628 Thu Apr 19 00:21:06 2001 ###Response### : Srvr# [3] =
[192.168.1.7:8001] load=1077584792 isGood=1077 546628 numSkip=1077546628 Thu Apr
19 00:21:06 2001 INFO: Reader::fill(): first=0 last=0 toRead=4096
Basically, the lastIndex=XXX appears to be random. It may do round-robin for 4
or 5
connections but then always it resorts to randomly directing new connections.
This is what the configuration looks like using the plug-in's
/weblogic?__WebLogicBridgeConfig URL:
Weblogic Apache Bridge Configuration parameters:
WebLogic Cluster List:
1.Host: '192.168.1.2' Port: 8001 Primary
General Server List:
1.Host: '192.168.1.2' Port: 8001
2.Host: '192.168.1.5' Port: 8001
3.Host: '192.168.1.7' Port: 8001
DefaultFileName: ''
PathTrim: '/weblogic'
PathPrepend: '' ConnectTimeoutSecs:
'10' ConnectRetrySecs: '2'
HungServerRecoverSecs: '300'
MaxPostSize: '0'
StatPath: false
CookieName: JSESSIONID
Idempotent:
ON FileCaching:
ON ErrorPage: ''
DisableCookie2Server: OFF
Can someone please help to shed some light on this? I would be really grateful,
thanks!
Jeff

Right - it means that the only configuration which can do perfect round-robin is a
single plugin (non-Apache, or single-process Apache) - all others essentially do random
(sort of, but it can skew test results during first N requests).
Robert Patrick <[email protected]> wrote:
Dimitri,
The way Apache works is that is spawns a bunch of child processes and the parent process
that listens on the port delegates the processing of each request to one of the child
processes. This means that the load-balancing dome by the plugin before the session ID is
assigned does not do perfect round-robining because there are multiple copies of the plugin
loaded in the multiple child processes. This situation is similar to the one you would get
by running multiple proxy servers on different machines with the NES/iPlanet and IIS
plugins.
As I pointed out in my response to Jeff, attempting to address this problem with IPC
machanisms would only solve the single machine problem and most people deploy multiple
proxy servers to avoid a single point of failure...
Hope this helps,
Robert
Dimitri Rakitine wrote:
Hrm. This is strange - I thought that all the information nesessary for a
'sticky' load-balancing (primary/secondary) is contained in the cookie/session info,
so, the particular plug-in implementation should not make any difference. For
load-balancing - statistically, given large enough sampling base, Apache plug-in
should perform just a well as NS one (unless apache is somehow misconfigured and
calls fork() for each new request).
Jeff Calog <[email protected]> wrote:
Robert,
Thanks for the sanity reply, you are definitely right. I used Netscape 3.0 on
Win2k and it did perfect round-robin load balancing to my servers.
<raving>
BEA - ARE YOU LISTENING? STOP TELLING PEOPLE YOUR APACHE PLUG-IN IS A VIABLE
LOAD BALANCING SOLUTION! It's worthless for load balancing!
</raving>
In some tests, as many as 90% of my connections/requests would be sent to a single
server. There should be something in the release notes like "By the way, the
Apache plug-in is only advertised as doing round-robin load balancing, in reality
it doesn't work worth a darn".
I'm surprised they don't used shared memory or some other technique (pipes, sockets,
signals, writing to /tmp, anything) for interprocess communication to fix that.
Jeff
Robert Patrick <[email protected]> wrote:
Yes, the problem lies in the fact that Apache uses multiple processes
instead of
multiple threads to process requests. Therefore, you end up with multiple
processes all
with the WebLogic plugin loaded into them (and they cannot see one another)...
Hopefully, Apache 2.0 when it comes out will allow the plugin to do a
better job...
Jeff Calog wrote:
I can't seem to get the Apache plug-in to actually do round-robin loadbalancing
of HTTP
requests. It does random-robin, as I like to call it, since the plug-inwill usually
hit all the
servers in the cluster but in a random fashion.
I've got three managed servers:
192.168.1.5:8001 (WL6 on Linux) 192.168.1.2:8001 (WL6 on Linux) 192.168.1.7:8001
(WL6 on Linux)
Admin server on 192.168.1.7:7000 (WL6 on W2k)
My Apache server is 1.3.9 (RedHat SSL) on 192.168.1.52.
The log file for each servers has something like this:
####<Apr 19, 2001 1:18:54 AM MDT> <Info> <Cluster> <neptune> <cluster1server1>
<main> <system> <> <000102> <Joined cluster cluster1 at address 225.0.0.5on port
8001>
####<Apr 19, 2001 1:19:31 AM MDT> <Info> <Cluster> <neptune> <cluster1server1>
<ExecuteThread: '9' for queue: 'default'> <> <> <000127> <Adding
3773576126129840579S:192.168.1.2:[8001,8001,7002,7002,8001,7002,-1]:192.168.1.52
to the cluster> ####<Apr 19, 2001 1:19:31 AM MDT> <Info> <Cluster><neptune>
<cluster1server1> <ExecuteThread: '11' for queue: 'default'> <> <><000127> <Adding
-6393447100509727955S:192.168.1.5:[8001,8001,7002,7002,8001,7002,-1]:192.168.1.52
to the cluster>
So I believe I have correctly created a cluster, although I did notbother to
assign
replication groups for HTTP session replication (yet).
The Apache debug output indicates it knows about all three serversand I can see
it
doing the "random-robin" load balancing. Here is the output:
Thu Apr 19 00:20:53 2001 Initializing lastIndex=2 for a list of length=3Thu Apr
19
00:20:53 2001 Init Srvr# [1] = [192.168.1.2:8001] load=1077584792 isGood=1077590272
numSk ip=134940256 Thu Apr 19 00:20:53 2001 Init Srvr# [2] = [192.168.1.5:8001]
load=1077584792 isGood=1077590272 numSk ip=134940256 Thu Apr 19 00:20:532001
Init Srvr# [3] = [192.168.1.7:8001] load=1077584792 isGood=1077590272numSk
ip=134940256 Thu Apr 19 00:20:53 2001 INFO: SSL is not configured ThuApr 19
00:20:53 2001 Now trying whatever is on the list; ci->canUseSrvrList= 1 Thu Apr
19
00:20:53 2001 INFO: New NON-SSL URL Thu Apr 19 00:20:53 2001 generallist: trying
connect to '192.168.1.7'/8001 Thu Apr 19 00:20:53 2001 Connected to192.168.1.7:8001
Thu Apr 19 00:20:53 2001 INFO: sysSend 320 Thu Apr 19 00:20:53 2001INFO:
Reader::fill(): first=0 last=0 toRead=4096 Thu Apr 19 00:21:06 2001parsed all
headers
OK Thu Apr 19 00:21:06 2001 Initializing lastIndex=1 for a list oflength=3 Thu
Apr 19
00:21:06 2001 ###Response### : Srvr# [1] = [192.168.1.5:8001] load=1077584792
isGood=1077 546628 numSkip=1077546628 Thu Apr 19 00:21:06 2001 ###Response###
: Srvr# [2] = [192.168.1.2:8001] load=1077584792 isGood=1077 546628
numSkip=1077546628 Thu Apr 19 00:21:06 2001 ###Response### : Srvr#[3] =
[192.168.1.7:8001] load=1077584792 isGood=1077 546628 numSkip=1077546628Thu Apr
19 00:21:06 2001 INFO: Reader::fill(): first=0 last=0 toRead=4096
Basically, the lastIndex=XXX appears to be random. It may do round-robinfor 4
or 5
connections but then always it resorts to randomly directing new connections.
This is what the configuration looks like using the plug-in's
/weblogic?__WebLogicBridgeConfig URL:
Weblogic Apache Bridge Configuration parameters:
WebLogic Cluster List:
1.Host: '192.168.1.2' Port: 8001 Primary
General Server List:
1.Host: '192.168.1.2' Port: 8001
2.Host: '192.168.1.5' Port: 8001
3.Host: '192.168.1.7' Port: 8001
DefaultFileName: ''
PathTrim: '/weblogic'
PathPrepend: '' ConnectTimeoutSecs:
'10' ConnectRetrySecs: '2'
HungServerRecoverSecs: '300'
MaxPostSize: '0'
StatPath: false
CookieName: JSESSIONID
Idempotent:
ON FileCaching:
ON ErrorPage: ''
DisableCookie2Server: OFF
Can someone please help to shed some light on this? I would be reallygrateful,
thanks!
Jeff
Dimitri--
Dimitri

Load balancing without a cluster...!!!!????

Hi boys!
          I have a question for you: my NES proxy server can realize a load
          balancing between 2 weblogic 6.0 servers that are NOT IN A CLUSTER?
          I've done some tests configuring the obj.conf like the 2 weblogic
          servers were in cluster, but I dont' understand if it works correctly.
          May be I ask too much ...
          Thanks
          Patrizia


          I'm assuming your using one browser to test this.
          The first time you access a servlet or a JSP that uses session
          tracking, the WL server will store a cookie in the browser. This
          cookie identifies the IP address and port number of the WLS where
          the request was executed (the Primary), and if it is a clustered
          configuation with session replication enable, also a Secondary
          server.
          The next time you make a request to iPlanet (or Apache), wlproxy
          looks at the cookie and directs you to the same WL server - so
          you won't see any load balancing.
          If you quit out of all your browsers, then start a new browser,
          and access it again, you won't have a WL cookie, and the request
          will get load balanced to one of the WL servers.
          Mike
          Patrizia MB <[email protected]> wrote:
          >Thanks Mike,
          >but I've some problems in verifying what you've asserted.
          >In my obj.conf I've put
          >
          > <Object name="wl" ppath="*/servlet/*">
          >
          > Service fn="wl-proxy" WebLogicCluster="10.0.0.3:7060,10.0.0.8:7060"
          >DebugConfigInfo="ON" Debug="ON"
          >
          > </Object>
          >
          >Note that I have 2 NOT-Clustered WLS instances behind
          >NES: I used
          >the "WebLogicCluster" property in the obj.conf only because
          >this
          >is the only way - as far as I know ! - to specify multiple
          >nodes to the
          >proxy.
          >
          >
          >With your suggestion, accessing the URL
          >"http://<your-nes-server>/?__WebLogicBridgeConfigInfo"
          >I can see this:
          > Query String: '__WebLogicBridgeConfig'
          > This entry is cluster aware.
          > ClusterID (from obj.conf): "10.0.0.3:7060,10.0.0.8:7060"
          > WebLogic Cluster List:
          > 1.Host: '10.0.0.8' Port: 7060 Primary
          > General Server List:
          > 1.Host: '10.0.0.3' Port: 7060
          > 2.Host: '10.0.0.8' Port: 7060
          >
          >
          >
          >
          >
          >In spite of that, there's no load-balancing!
          >I checked the 2 access files on the 2 nodes, and I see
          >that all my
          >requests go to the same server 10.0.0.8.
          >Why?
          >According to which logic 10.0.0.8 has been defined the
          >Primary? (They
          >are both Administration Servers)
          >
          >I hope you'll answer to my questions!
          >
          >TIA
          >
          >Patrizia
          >
          >
          >
          >
          >
          >
          >Mike Reiche wrote:
          >
          >> The wlproxy for NES will round-robin requests to multiple
          >WL
          >> servers if they are clustered or not clustered.
          >>
          >> You can get some additional information by adding the
          >property
          >> DebugConfigInfo=ON to the WL configuration in obj.conf
          >then
          >> hitting the URL...
          >> http://<your-nes-server>/?__WebLogicBridgeConfigInfo
          >>
          >> Check the WL NSAPI doc.
          >>
          >> Mike
          >>
          >> Monteforte Patrizia <[email protected]>
          >wrote:
          >> >Hi boys!
          >> >I have a question for you: my NES proxy server can
          >realize
          >> >a load
          >> >balancing between 2 weblogic 6.0 servers that are
          >NOT
          >> >IN A CLUSTER?
          >> >I've done some tests configuring the obj.conf like
          >the
          >> >2 weblogic
          >> >servers were in cluster, but I dont' understand if
          >it
          >> >works correctly.
          >> >May be I ask too much ...
          >> >
          >> >Thanks
          >> >
          >> >Patrizia
          >> >
          >

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

Load Balancing and Failover with 10G Standard Edition

Hi,
I am new to Oracle Replication and need some help setting up replication for load balancing and failover. Is this possible using Oracle 10G Standard Edition? I plan on having all updates done on the master site and both databases will be for reads. In case of failure of the master site, I would need to be able to failover to the other database.
Also, if anyone knows of any documention for Basic Replication in 10G, please let me know.
Thanks.

Simple nnapshot replication of data would require significant manual effort to configure to load balance or failover. One the load balancing side, you would generally be limited to to static load balancing-- assigning half the users to one machine and the other half of the users to the other machine, regardless of who is actively using the machine. Failover would be a significant manual effort, particularly to bring the failed machine back into the cluster. You would be implementing the guts of multi-master replication.
Frankly, if you actually have a system which is valuable enough to need load balancing and disaster recovery, I'm going to wager that it will be far cheaper even in the short run to buy more boxes and/or enterprise edition licenses than to try to implement this sort of thing yourself. In the long run, it will be far cheaper, since it will be far easier to maintain. Building all this yourself would probably be penny wise and pound foolish.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

Load balancing vs Replication

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