RAC环境下的Rman channel管理(原创)

Crosschecking on Multiple Oracle Real Application Clusters Nodes

When crosschecking on multiple nodes (and when operating RMAN in general), configure the cluster so that all backups can be accessed by every node, regardless of which node created the backup. When the cluster is configured this way, you can allocate channels at any node in the cluster during restore or crosscheck operations.

If you cannot configure the cluster so that each node can access all backups, then during restore and crosscheck operations, you must allocate channels on multiple nodes by providing the CONNECT option to the CONFIGURE CHANNEL command, so that every backup can be accessed by at least one node. If some backups are not accessible during crosscheck because no channel was configured on the node that can access those backups, then those backups are marked EXPIRED in the RMAN repository after the crosscheck.

For example, you can use CONFIGURE CHANNEL ... CONNECT in an Oracle RAC configuration in which tape backups are created on various nodes in the cluster and each backup is only accessible on the node on which it is created. This is described in more detail in "Configuring Channels to Use a Specific Channel" .

Configuring Channels for RMAN in Oracle Real Application Clusters

This section describes how to configure channels for RMAN. You can configure channels to use automatic load balancing or you can specify specific channels for specific instances as described in the following topics:

Configuring Channels to Use Automatic Load Balancing

To configure channels to use automatic load balancing, use the following syntax:
     CONFIGURE DEVICE TYPE [disk | sbt] PARALLELISM number of channels;

Where number of channels is the number of channels that you want to use for the operation. After you complete this one-time configuration, you can run BACKUP or RESTORE commands.

Configuring Channels to Use a Specific Channel

To configure one RMAN channel for each Oracle RAC instance, use the following syntax:

CONFIGURE CHANNEL DEVICE TYPE sbt CONNECT
'SYS/change_on_install@node1'
CONFIGURE CHANNEL DEVICE TYPE sbt CONNECT
'SYS/change_on_install@node2'

After this one-time configuration step, you can run the BACKUP or RESTORE commands. In addition, you can use the PARMS command in this example to set vendor-specific parameters.

注意10g下在配置configure channel **** connect 选项时安全性已经做了很大的改进，请看如下示例

配置configure channel **** connec

RMAN> configure channel device type disk connect 'sys/2988864@czmmiao';
new RMAN configuration parameters:
CONFIGURE CHANNEL DEVICE TYPE DISK CONNECT '*';
new RMAN configuration parameters are successfully stored

查看 configure channel **** connect

RMAN> show  channel ;
RMAN configuration parameters are:
CONFIGURE CHANNEL DEVICE TYPE DISK CONNECT '*';
显示的时候已经显示为‘*’号了

在RAC环境下，建议采用configure channel **** connect配置。原因如下：

1、如果在备份时失败了，由于channel连接到了不同的node，可以继续进行备份。

2、配置不同的channel连接到不同的node可以使备份在负载较小的节点上进行，有利于负载均衡。

3、如果有数据库文件如归档日志，联机日志，控制文件等位于node的磁盘上而不是位于共享磁盘上，那么必须配置configure channel **** connect，否则无法备份相应文件。

参考至：https://forums.oracle.com/forums/thread.jspa?threadID=537755

              http://yangtingkun.itpub.net/post/468/472593

              http://download.oracle.com/docs/cd/B28359_01/rac.111/b28254/rman.htm

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