In the past few years, technology has become a very important aspect of our lives. Can you imagine a day when you are unable to connect to. Can you imagine a day when you are unable to connect to your email or unable to check the latest updates from your friends from Facebook or Twitter? In addition to this several parts of our life are inextricably connected with technology today. Again the answer would be a no I believe!
Though technology is meant to make our lives simpler, faster and easier, at the end of the day it is a human invention and is therefore fallible. So you see, machines may fail, may become overloaded, may become obsolete and whenever any such thing happens, the technology running on that machine also ceases! If the technology stops, you stop as well! Hence come the numerous solutions for HA!
There are a variety of solutions provided by a large number of vendors and so is done by Oracle Corp as well. But the issue is Oracle RAC is a solution which is not affordable for quite a few shops. This is what Oracle Corp brought out with Well, yes it is —sort of! This was known as Cold Cluster Failovera topology using which the crash of a single instance of a database could be made to do a failover to another node using the cluster services.
This technique was applicable to the databases of release Needless to say that the nodes were supposed to use a shared storage. Also, it was mandatory to use Application VIP to make sure that the client is unaware about the existence of such a configuration. Though the solutions seem to appear almost fool-proof, its implementation was the real challenge. An intensive manually driven process would be required to achieve this HA of single instance.
As discussed, the functionality was available in the previous versions as well but it was quite challenging to implement. RAC One node, introduced in RAC One Node is a better high availability solution than traditional cold fail over solutions. RAC One Node operates in a cluster but only a single instance of the database is running on one node in the cluster. If that database instance has a problem, RAC One Node detects that and can attempt to restart the instance on that node If the whole node fails,RAC One Node will detect that and will bring up that database instance on another node in the cluster.
Unlike traditional cold failover solutions, Oracle Clusterware will send out notifications FAN events to clients to speed reconnection after failover. RAC One Node goes beyond the traditional cold fail over functionality by offering administrators the ability to proactively migrate instances from one node in the cluster to another.
For example, lets say you wanted to do an upgrade of the operating system on the node that the RAC One Node database is running on. Once the instance and all of the connections have migrated, the server can be shut down, upgraded and restarted. OMotion can then be invoked again to migrate the instance and the connections back to the now-upgraded node. This non-disruptive rolling upgrade and patching capability of RAC One Node exceeds the current functionality of the traditional cold fail over solutions.
For example, if you have two different database instances running on a RAC One Node Server and it becomes apparent that the load against these two instances is impacting performance, the DBA can invoke OMotion and migrate one of the instances to another lessused node in the cluster. RAC One Node offers this load balancing capability, something that the traditional cold fail over solutions do not.
Lastly,many 3rd-party solutions do not support ASM storage. This can slow down failover, and prevent consolidation of storage across multiple databases, increasing the management burden on the DBA.
The following table summarizes the differences between RAC One Node and 3rd-party fail over solutions:. This option adds to the flexibility that Oracle offers for reducing costs via consolidation. RAC One Node offers better high availability functionality than traditional cold failover cluster solutions because of a new Oracle technology Omotionwhich is able to intelligently relocate database instances and connections to other cluster nodes for high availability and system load balancing.
You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. This site uses Akismet to reduce spam.During installation, click Help to find explanations of options and prompts for each installation screen, and click Details to see the log file.
Setup Wizard Installation Options for Creating Images Before you start the setup wizards for your Oracle Database or Oracle Grid Infrastructure installation, decide if you want to use any of the available image-creation options. About Deploying Oracle Databases Using Rapid Home Provisioning Rapid Home Provisioning provides a standardized approach for provisioning, patching and upgrading software homes on any number of nodes from a single cluster.
See Also: During installation, click Help to find explanations of options and prompts for each installation screen, and click Details to see the log file.It contains the following sections:. BDA 8. One advantage of this feature is that, for a planned migration, a RAC One Node environment works effectively because it enables you to continue work without impacting the business by relocating the instance from one node to another while moving the sessions along with it. Introduced in Oracle version RAC One Node, on the other hand, works as an Active-Passive solution where only one node can be active at a time, and the other nodes are available to accept the workload in the case of a planned or an unplanned downtime related to the first node.
Only during a planned online database relocation is a second instance of an Oracle RAC One Node database created, so that any database sessions can continue while the database is relocated to a new node. If you are performing a first-time installation, see Performing the installation. If you are installing a service pack or patches, see Applying maintenance, patches, or fixes.
If you are performing an upgrade, see Upgrading a Standalone Manager for standalone configurations or Upgrading a Multi-Manager configuration for megamesh configurations. Under the object in Context Tree, the cluster node where the database was created is displayed as an application Instance with a green icon, indicating that it is an active RAC One Node instance.
In the Action page, select a template and an execution sequence, and click Next. For additional details of the procedures demonstrated in this walkthrough, including explicit details of the options in each wizard page, see the following topics:. Recently Viewed Pages. Hint: type "g" and then "r" to quickly open this menu.
BMC Database Automation 8. Pages Blog. Page tree. Browse pages. Remove Read Confirmation. A t tachments 17 Page History. Add Page Properties. Dashboard … Home Getting started Getting started with Oracle. Jira links Workflow Read Confirmation. Created by Bob Massalast modified on Apr 26, Task Description Plan your deployment. Planning all aspects of your deployment, including system requirements and security, ensures a successful implementation.
When planning access control, note that RAC One Node capabilities have been mapped to existing Oracle capabilitiesand no new ones are required. Download the installation files, including the Additional Utilities folder.
The installation program for the latest service pack or patch also includes the full installation of the product. To install the product for the first time or apply product updates, select the Additional Products tab and download the latest service pack or patch. You can find the latest information about service packs and patches under Release notes and notices. You must perform these tasks before you launch the installation program.
RAC One Node
Procedure Example screens 1 Add a database to an Oracle cluster. From the Management Console, select the cluster within which you want to create an Oracle database. Step through the wizard until you get to the Configuration page. In the Database Options page, check the boxes for each of the database options you want.
The figure to the right shows the Oracle This protects against unplanned server outages because transparent application failover will re-direct to another server, and also aids the RAC goal of scalability, when a new server instance is genned-in to the RAC cluster. RAC One Node claims to be a multiple instances of RAC running on a single node in a cluster, and has a fast "instance relocation" feature in cases of catastrophic server failure.
This instance relocation uses a new featured dubbed Oracle Omotion. This is a Back to the Future approach, a movement back to the monolithic server environments of the 's, with all of their benefits:. See my notes here on Oracle server consolidation and the 2nd age of mainframe computing. In RAC we achieve continuous availability because that is little or no latency as TAF redirects transactions to surviving server when a server crashes or a node become unavailable.
To understand how RAC One Node might do a fast instance relocation, lets examine similar offerings by 3rd party vendors. This database switch enables Oracle databases to be transparently relocated onto new servers without the need to modify applications connections to the database. The database servers, in turn, are connected to a shared storage such as SAN, such that database files can be quickly remapped onto a different server. Virtualization allows for instance relocation between servers.
Here is how instance relocation worked in earlier offerings by 3rd parties. Using IP address masks enables virtualization of database addresses. This allows the Database Area Network to move Oracle instances without affecting the application server layer. The internal mechanism in Omotion for fast Oracle instance relocation may be quite complex, but the idea is simple.
In the olden days, we did this with a SAN environment, using the following steps:. The Oracle instance or the server crashes.
A dead connection probe DCD detects the outage and we un-mount the SAN data file systems from the source server if it's awake. We then mount the database files onto the failover server using SAN. We re-start the instance on the new server, using a pre-loaded init. A typical time for an Oracle instance relocation is less than 20 seconds, not true continuous availability, but certainly better than a catastrophic unplanned outage.
Again, Oracle has not published the internal machinations of their instance relocation strategy, but it's a safe bet that it happens very quickly over SAN storage. Oracle RAC One Node also buys in to the industry-wide server consolidation movement, whereby instances are consolidated for better quality management and resource sharing. The hardware industry is also embracing this "scale up" approach by providing servers with lots of slots for future expansion.
For example, the Sun Fire X Server, allows from 12 to 48 processors and up to gig RAM, allowing the DBA to add server resources just-in-time to meet increases in processing demands.
Feel free to ask questions on our Oracle forum. Verify experience!This option adds to the flexibility that Oracle offers for database consolidation. You can consolidate many databases into one cluster with minimal overhead while also providing the high availability benefits of failover protection, online rolling patch application, and rolling upgrades for the operating system and Oracle Clusterware.
You can limit the CPU consumption of individual database instances per server within the cluster through Resource Manager Instance Caging and dynamically change this limit if needed. With Oracle RAC One Node, there is no limit to server scalability and if applications grow to require more resources than a single node can supply, then you can easily upgrade your applications online to Oracle RAC.
If the node that is running Oracle RAC One Node becomes overloaded, then you can relocate the instance to another node in the cluster using the online database relocation utility with no downtime for application users. Using Oracle RAC One Node online database relocation, you can relocate the Oracle RAC One Node instance to another server, if the current server is running short on resources or requires maintenance operations, such as operating system patches.
RAC One Node tips
You can use the same technique to relocate Oracle RAC One Node instances to high capacity servers to accommodate changes in workload, for example, depending on the resources available in the cluster. In addition, Resource Manager Instance Caging or memory optimization parameters can be set dynamically to further optimize the placement of the Oracle RAC One Node instance on the new server. Relocating an Oracle RAC One Node instance is therefore mostly transparent to the client, depending on the client connection.
Oracle recommends to use either Oracle Fast Application Notification or Transparent Application Failover to minimize the impact of a relocation on the client. For administrator-managed Oracle RAC One Node databases, you must monitor the candidate node list and make sure a server is always available for failover, if possible. Candidate servers reside in the Generic server pool and the database and its services will fail over to one of those servers.
For policy-managed Oracle RAC One Node databases, you must ensure that the server pools are configured such that a server will be available for the database to fail over to in case its current node becomes unavailable.
Also, for policy-managed Oracle RAC One Node databases, the destination node for online database relocation must be located in the database's server pool. For example:. If the Oracle RAC database is administrator managed, then you must change the configuration of all services to set the preferred instance to the instance that you want to keep as an Oracle RAC One Node database after conversion.
These services must no longer have any available instance. If the database is up and running and you do not specify the node where the database is running, then the command returns an error instructing you to specify the node. If you are relocating the database you want to convert to Oracle RAC using online database relocation, or an online database relocation has failed, then you must either abort or complete the relocation before you run the srvctl convert database command.
After you convert the database, you can add instances using DBCA. It also results in reusing the server pool in which the database currently runs. The conversion reconfigures the database to run on all nodes in the server pool. The command does not start any additional instances but running the srvctl start database command starts the database on all nodes in the server pool. You can relocate an Oracle RAC One Node database to another node while still maintaining service availability using the online database relocation utility.
Only during a planned online database relocation is a second instance of an Oracle RAC One Node database created, so that any database sessions can continue while the database is relocated to a new node. If your Oracle RAC One Node database is administrator managed, then the target node to which you want to relocate the database must be in the candidate list or in the Free server pool.
If the target node is in the Free server pool, then the node is added to the candidate list. You must recopy both of these files to all candidate nodes every time you update the password file. This is true for both policy-managed and administrator-managed databases.
Oracle recommends using OS authentication, instead, or using Oracle Clusterware to start and stop the database, and defining users in the data dictionary for other management. Note: In order to cover all failure scenarios, you must add at least one dynamic database service Oracle Clusterware-managed database service to an Oracle RAC One Node database. If you do not specify an instance prefix, then the first 12 characters of the unique name of the database becomes the prefix.
The same instance name is used on failover. See Also: "convert" for more information. Online Database Relocation You can relocate an Oracle RAC One Node database to another node while still maintaining service availability using the online database relocation utility.The material covered here will be indispensable in my work.
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