Oracle RAC - Failover and Load (free love spells) Balancing
No commentsBy hitechwriter
Failover
Oracle RAC systems provide two methods of failover to provide reliable access to data:
Connection failover.
If a connection failure occurs at connect time, the application can fail over the connection to another active node in the cluster. Connection failover ensures that an open route to your data is always available, even when server downtime occurs.
Transparent Application Failover (TAF).
If a communication link failure occurs after a connection is established, the connection fails over to another active node. Any disrupted transactions are rolled back, and session properties and server-side program variables are lost. In some cases, if the statement executing at the time of the failover is a Select statement, that statement may be automatically re-executed on the new connection with the cursor positioned on the row on which it was positioned prior to the failover.
The primary difference between connection failover and TAF is that the former method provides protection for connections at connect time and the latter method provides protection for connections that have already been established. Also, because the state of the transaction must be stored at all times, TAF requires more performance overhead than connection failover.
Connection Failover
Enabling connection failover allows a driver to connect to another node if a connection attempt on one node fails. When an application requests a connection to an Oracle database server through the driver, the driver does not connect to the database server directly. Instead, the driver sends a connection request to a listener process, which forwards the request to the appropriate Oracle database instance. In an Oracle RAC system, each active Oracle database instance in the RAC system registers with each listener configured for the Oracle RAC.
Transparent Application Failover (TAF)
With TAF, if a communication link failure occurs after a connection is established, the connection is moved to another active Oracle RAC node in the cluster without the application having to re-establish the connection.
Load Balancing
Oracle RAC systems provide two types of load balancing for automatic workload management:
Server load balancing distributes processing workload among Oracle RAC nodes.
Client load balancing distributes new connections among Oracle RAC nodes so that no one server is overwhelmed with connection requests. For example, when a connection fails over to another node because of hardware failure, client load balancing ensures that the redirected connection requests are distributed among the other nodes in the RAC.
The primary difference between these two methods is that the former method distributes processing and the latter method distributes connection attempts.
Server Load Balancing
With Oracle9i RAC systems, a listener service provides automatic load balancing across nodes. The query optimizer determines the optimal distribution of workload across the nodes in the RAC based on the number of processors and current load.
Oracle 10g also provides load-balancing options that allow the database administrator to configure rules for load balancing based on application requirements and Service Level Agreements (SLAs). For example, rules can be defined so that when Oracle 10g instances running critical services fail, the workload is automatically shifted to instances running less critical workloads. Or, rules can be defined so that Accounts Receivable services are given priority over Order Entry services.
The DataDirect Connect for ODBC Oracle drivers can transparently take advantage of server load balancing provided by an Oracle RAC without any changes to the application. If you do not want to use server load balancing, you can bypass it by connecting to the service name that identifies a particular RAC node.
Client Load Balancing
Client load balancing helps distribute new connections in your environment so that no one server is overwhelmed with connection requests. When client load balancing is enabled, connection attempts are made randomly among RAC nodes. You can enable connection failover for DataDirect Connect for ODBC drivers through a driver connection string using the Load Balancing connection string attribute.
Suppose you have the Oracle RAC environment shown in Figure 4 with multiple Oracle RAC nodes, A, B, C, and D. Without client load balancing enabled, connection attempts may be front-loaded, meaning that most connection attempts would try Node A first, then Node B, and so on until a connection attempt is successful. This creates a situation where Node A and Node B can become overloaded with connection requests.
With client load balancing enabled, the driver randomly selects the order of the connection attempts to nodes throughout the Oracle RAC system. For example, Node B may be tried first, followed by Nodes D, C, and A. Subsequent connection retry attempts will continue to use this order. Using a randomly determined order makes it less likely that any one node in the Oracle RAC system will be so overwhelmed with connection requests that it may start refusing connections.
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Boxing and martial art equipment following the dress code!
By Ingrid Sure
A sport with an incredible history, Muay Thai is practiced by people of various ages, all interested in rediscovering their limits. They have come to rely on the Internet in order to find the equipment they need. Among the products that can be purchased online, we can include: boxing shorts, Thai oil and training aids. Of course, shin guards are also available. These represent protective garment, made from a hard material in order to offer protection for the shin. Muay Thai is not the only sport in which shin guars are often worn, youll probably see them in hockey players as well.
In modern times, Muay Thai is not the same sport as it used to be. New rules have been applied and the equipment resembles more and more Western boxing. Thus, you should not be surprised if the boxing gloves you find online look really similar to the ones you see on American boxers. Nevertheless, its important that you understand that there is a very strict dress code for anyone interested in practicing this sport. There is no other garment than the one comprised of boxing shorts and gloves accepted. Moreover, the color of the chosen Muay Thai shorts should fit to the corner one starts the match from.
As the Internet has become our number one resource for shopping, we should not be amazed with the diversity of products invading virtual stores. Thanks to such developments, one can find Muay Thai shorts, Thai oil and training aids available online. The equipment is suitable for boxing and martial art practicing, being of the highest quality possible and brought straight from the home country of Muay Thai, meaning Thailand. The prices are more than affordable and you will certainly be impressed with the products they provide for interested customers. We are talking about the best boxing gloves you have ever seen, plenty of training aids to put to good use and shin guars for protection.
No matter the product you are interested in white boxing gloves, Inter Muay Thai shorts or Thai oil there is complete information for you to read. Choose the quantity and then see the other specifications for the products, such as the weight or price. If you have been satisfied with the purchases made, then dont be afraid to tell a friend about the website or provide some customer feedback. Other shoppers will appreciate your effort and purchase boxing gloves or other products with confidence. As for you, check out the best sellers and recommended product list so as to see whats hip. Muay Thai short are definitely amongst the most popular!
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Welcome to Muay Thai Depot Inc. We sell boxing and martial arts equipment imported directly from Thailand. We specialize in equipment for training in Muay Thai. All our equipment is hand made in Thailand.
Married Dating - Is it Worth It?
By Kelly Purden
Infidelity is definitely a sin, but the fact doesn’t stop some married people from dating other individuals. Maybe their marriage is on the rocks, or their marriage lacks excitement. Whatever the reasons are, there will always be spouses who will stray and date other people. The question is, are they dating single people or are they dating married individuals like themselves?
Believe it or not, but there are online services that cater to those married people who want to date outside their marriage. These married dating sites may sound immoral to some, but the service can be likened to escort services. They are discreet about it, and it will provide a safe haven for those who want to indulge in forbidden pleasures. Whether you like it or not, there are more and more “married but dating” individuals out there who’d like to break out of the monotony of their married lives and explore what’s on the other side of the fence.
What exactly do these married dating sites offer? They allow married individuals to join a community of users who are also married and looking for dates and casual encounters. The sites offer them ultimate discretion and protection when using their services. How these sites work is pretty much the same as the standard online dating services; there are messaging services you can use to chat with other members, e-mail and match-making services.
Is married dating worth it? Depends on who you ask. Conservatives will automatically tell you that it’s wrong and there are no excuses to cheat on your spouse; on the other hand, liberal-minded people will tell you that as long as it’s done discreetly, it’s all good. And discretion is where these married dating sites are all about.
There are lots of married dating sites where you can sign up and join.
1. WildMatch
The site promises sexy partners, single or dating. Quite simply, it’s a place where people can look for sex and get it.
2. SexyAds
It features “lonely housewives” who need some loving, according to the website. The service promises hookups with no strings attached. It’s an adult personal community where married people can go look for other married people and enjoy consensual pleasures.
3. MarriedSecrets
It’s an online dating site which provides married people new ways to have fun. The site guarantees “a fun-filled affair with like-minded adults.”
4. BangMatch
BangMatch is considered as one of the top adult dating sites around. Easy sex is their promise; it can’t any simpler than that. The site further guarantees that they have a big number of women waiting to cheat on their husbands. Perfect for married dating encounters.
5. DiscreetAdventures
For married women and men looking for hush-hush encounters, the site provides a safe and anonymous way for married ones to experience illicit, extra-marital excitement. There are some nifty features, where a member can send kisses to other members, signifying that he is interested in them. It is also equipped with basics such as e-mail, instant messaging, and match-finder service.
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Tuesday, August 26th, 2008 at 11:50 pm and is filed under love. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
