When you copy data from source to destination store, the copy activity provides certain level of fault tolerances to prevent interruption from failures in the middle of data movement. For example, you are copying millions of rows from source to destination store, where a primary key has been created in the destination database, but source database does not have any primary keys defined. When you happen to copy duplicated rows from source to the destination, you will hit the PK violation failure on the destination database. At this moment, copy activity offers you two ways to handle such errors:
For example: Copy data from a CSV file in Blob storage to a SQL database with a schema definition that contains three INT type columns. The CSV file rows that contain numeric data, such as 123,456,789 are copied successfully to the sink store. However, the rows that contain non-numeric values, such as 123,456, abc are detected as incompatible and are skipped.
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For example: Copy data from a CSV file in Blob storage to a SQL database with a schema definition that contains six columns. The CSV file rows that contain six columns are copied successfully to the sink store. The CSV file rows that contain more than six columns are detected as incompatible and are skipped.
For example: Copy data from a SQL server to a SQL database. A primary key is defined in the sink SQL database, but no such primary key is defined in the source SQL server. The duplicated rows that exist in the source cannot be copied to the sink. Copy activity copies only the first row of the source data into the sink. The subsequent source rows that contain the duplicated primary key value are detected as incompatible and are skipped.
By making a single-instance Oracle Database highly available, you ensure that even when a cluster node is shut down or fails, applications that access that database suffers only a momentary loss of connection with the database while the database is restarted on another cluster node. Applications can automatically reconnect to the database after such a failover event occurs using transparent application failover, resulting in a failover that is not apparent to users.
Oracle Fail Safe Server discovers standalone single-instance databases (those that are not in a cluster group) by looking for Oracle Database instance Windows services. Any service found on any cluster node that is not currently in a cluster group is displayed in the Oracle Fail Safe Manager's Available Oracle Resources list.
To avoid this problem, the listener must use the node IP address for its host entry instead of the host name. Whenever Oracle Fail Safe validates a cluster group or adds a database to a group, it searches ADDRESS entries that have a HOST set to the local node's host name. All HOST entries that use the local node name change to use the IP address for the node.
When a database is configured for high availability, Oracle Fail Safe makes adjustments to the default listener. This affects the Oracle Net configuration for all databases, including standalone databases. Therefore, all standalone databases in an Oracle Fail Safe environment require some adjustments to the Oracle Net configuration if any database in the cluster has been made highly available.
If the shared server configuration for standalone single-instance databases relies on the default listener, then no listener parameters are specified in the database parameter file. (The default listener is a listener that listens on the host name of the node, the default port number, and TCP protocol.) In this case, the configuration will no longer work after Oracle Fail Safe has changed the default listener to use an IP address in place of the host name.
Oracle Fail Safe does not attempt to maintain listener SID lists. If you have an application that requires a cluster database to be in the listener's SID list, then manually edit the appropriate listener.ora file on each node of the cluster.
When Oracle Fail Safe searches for a standalone database listener, it scans the listener Windows services to find one that is listening on the network address used by the database. If there are multiple listeners that are listening on a network address, then Oracle Fail Safe selects the listener service that is running. If none of the listeners are started, then Oracle Fail Safe chooses the first listener found that is listening on the network address.
All files used by the single-instance database must be on the shared cluster disks, except the database initialization parameter file, which can be placed on a private disk or on a shared cluster disk. See Section 7.3.3.4 for more information about the placement of the initialization parameter file.
From Oracle Resources view, choose Create Sample Database action from the Actions menu in the right pane of the screen. You can use this sample database to try out the features of Oracle Fail Safe before using them on a production database. Do not use the sample database for production work.
Select the resource that you want to verify from the Available Oracle Resources list, then select Validate from the Actions menu of the Oracle Resources view. This operation performs validation checks to ensure that the standalone database is configured correctly on the node where it resides and to remove any references to the database that may exist on other cluster nodes.
Microsoft failover clusters allow you to use any text string for the name of a resource. By default, Oracle Fail Safe uses the instance ID for the database. You can change the name to something more meaningful, if desired. For example, the cluster resource name is changed to Test Database here.
If you are adding a database to a group and the cluster consists of more than two nodes, then you are asked to specify the nodes which must be possible owners for the database by specifying a list of selected nodes, as shown in Figure 7-2. To specify that a particular node must not be a possible owner for the database, select the node from the Selected Nodes list and click the left arrow.
If you are adding a single-instance database to a group and the cluster consists of two or more nodes, but one or more nodes are unavailable, then you are also asked to specify which nodes must be possible owners for the database. In this case, the wizard page displays which nodes are unavailable, as shown in Figure 7-3.
If the group to which you are adding a single-instance database contains multiple network names, then the Add Resource to Group Wizard asks you to specify the network name or names for the listener, as shown in Figure 7-4. This page is not displayed if the group to which you are adding a database contains only one network name.
Oracle Fail Safe includes support for multiple network names in a group. All databases in a group must use the same network names, and the network names must be added to the group before you add the databases to the group. The sequence for building a group is as follows:
For example, if a group contains a database that is using two network names and you add a second database to the group, then the second database must use the same network names as the first database that was configured into the group. Oracle Fail Safe Manager checks to ensure that the same network names are used for all single-instance databases that you add to a group.
Oracle Fail Safe uses this data to configure the database into the cluster (for example, to update the tnsnames.ora file). It also passes the data that you supply to Microsoft Windows Failover Clusters, where it is registered for use when the database is brought online, taken offline, or when Is Alive polling is performed. Oracle Fail Safe requests the name and location of the initialization parameter file.
When an Oracle Database starts, it uses the initialization parameter file to specify the name of the database, the amount of memory to allocate, the names of control files, and various limits and other system parameters.
In most cases, place the parameter file on a cluster disk so that it can be accessed regardless of which cluster node is currently hosting the database. However, a copy of the initialization parameter file can be placed on each node's private disk, if you ensure that the file exists at the same location on all cluster nodes that are configured to run a database. You may decide to place the parameter file on each node's private disk to set different parameters for the database, depending on which node is hosting it. This can be useful if some nodes have less memory or processing capabilities than others.
Oracle Fail Safe requires that a text initialization parameter file (PFILE) be specified in the Parameter File field. To use a binary server parameter file (SPFILE) with databases configured for high availability, specify the location of the SPFILE from within the PFILE using the SPFILE=SPFILE-location parameter. The SPFILE must reside on a shared disk that is a member of the cluster group where the database resides. For example, the contents of the PFILE may include the following parameters:
All Oracle database instances on each node of the cluster must use the same SPFILE and the file must be on shared storage. If the SPFILE is not currently stored on a shared disk, then create a copy using SQL*PLUS as follows:
The Authentication page is presented if the account under which Oracle Fail Safe was installed is not in one of the following Windows operating system groups: the ORA_DBA group, the ORA_SID_DBA group, or the ORA_home_DBA group associated with the database. When the account under which Oracle Fail Safe was installed is in the ORA_DBA group, the ORA_SID_DBA group, or the ORA_home_DBA group, it can use operating system authentication to access the database. If the account is not a member of the ORA_DBA group, the ORA_SID_DBA group, or the ORA_home_DBA group, then it must use the SYS account to access the database.
Finally, the Add Resource wizard asks you to confirm the operation. Note that the cluster group will be taken offline during the Add operation. The database and any resources in the group will be unavailable while Oracle Fail Safe adds the database to the group. Click Finish to complete the task of adding the Oracle Database to group. 2ff7e9595c
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