Basic concepts of oracle RAC DRM

The basic concept of oracle rac drm is in oracle RAC. Each instance has a data cache pool, and each block change coordinates resources among instances to maximize performance, this ensures data integrity. In a RAC cluster, each cached data copy, also called a cache resource, has an instance called a master node. In 10.1.0.2, once a cache resource is master, the re-remaster of the cache resources or the automatic change of the master node only happens to the normal start and stop of the RAC instance node or abnormal problems between cluster management resources. Www.2cto.com that is to say, if node B is a master NODE of the cache resource, the resource will be routed from master to node B until the RAC NODE is reconfigured.
Introducing a new Resource remaster concept in oracle 10 Gb is called DRM (Dynamic Resource management [ID 390483.1, reconfiguration of RAC instance nodes is no longer A factor for cache resources to be remaster. If cache resources are frequently accessed by node a, A resource can be remaster from node B to NODE.
Some other concepts are as follows: In 10gR1 DRM is driven by affinity of files and in 10gR2 it is based on objects. DRM attributes are intentionally uninitialized ented since they may change depending on the version. these attributes shocould 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. www.2cto.com
DRM login cause "latch: cache buffers chains" and "latch: object queue header operation" wait event, you can go throught this way to disable DRM: _ gc_affinity_time = 0 _ gc_undo_affinity = FALSEalso, you can used another two implicit parameters dynamic parameters = 10000000 _ gc_affinity_minimum = 10000000 the value above can be changed as required. Author: Yu guanghong