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oracle RAC DRM基本概念

 2012-08-04 22:39:50 来源:WEB开发网   
核心提示: 在oracle RAC中,每个实例均存在一个数据缓存池,oracle RAC DRM基本概念,每个block的改变都将实例间进行资源协调以获取最大化性能,从而保证数据的完整性,RAC实例节点的重新配置已经不再是cache资源被重新remaster的因素,如果cache resource被节点A频繁访问,在RAC集群中

 在oracle RAC中,每个实例均存在一个数据缓存池,每个block的改变都将实例间进行资源协调以获取最大化性能,从而保证数据的完整性。
在10.1.0.2中,一旦一个cache resource被master一个实例节点,
也就是说,如果NODE B是一个缓存资源的master节点,这个资源将被一直master到NODE B直到发生RAC节点的重新配置操作。
在oracle 10g中引进一个新的资源remaster概念叫做DRM(Dynamic Resource management [ID 390483.1]),通过DRM,RAC实例节点的重新配置
已经不再是cache资源被重新remaster的因素,如果cache resource被节点A频繁访问,一个资源可以从NODE B remaster到NODE A。
In 10gR1 DRM is driven by affinity of files and in 10gR2 it is based on objects.
DRM attributes are intentionally undocumented since they may change depending on the version. These attributes should not be changed without discussing with Support.
Two instance will not start a DRM operation at the same time however lmd,lms,lmon processes from all instances collectively take part in the DRM operation.
Normal activity on the database is not affected due to DRM. This means users continue insert/update/delete operations without any interruptions. Also DRM operations complete very quickly.
DRM many cause" latch: cache buffers chains" and "latch: object queue header operation " wait event, you can go throught this way to disable DRM:
also, you can used another two implicit parameters dynamic change

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