Oracle Tips by Burleson

Oracle10g Grid Computing with RAC
Chapter 7 - Cache Fusion and Inter Instance Coordination

Recovery Process – Re-mastering Resources

Thus, after the first pass, the recovering instance will have locks on every block in the recovery list (set). Other instances will not be able to acquire these locks until the recovery operation is completed. Now the second pass begins, the redo is applied to the data files.

During instance recovery, if the recovering instance dies, a surviving instance (if one exists) will acquire instance recovery enqueue and starts recovery. If a non-recovering instance fails, SMON will abort recovery, release the IR enqueue, and the next live instance will reattempt instance recovery.

Conclusion

This chapter has explained the nature of cache fusion, resource coordination, cache-to-cache transfers, resource management, and lock conversions. It also discussed instance failure and the associated re-mastering of resources by the surviving instance.

The main points of this chapter include:

• Cache fusion technology avoids expensive block pings (or forced writes to disk). Data blocks are shipped across the nodes (or instances) by means of the interconnect technology.
   

• Local caches of all instances in the cluster fuse to form a global cache. Therefore, it is called cache fusion. There are additional background processes to manage the global cache service (GCS).