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Showing posts from February, 2015

Oracle RAC Interview Questions and Answers

How does OCSSD starts first if voting disk & OCR resides in ASM Diskgroups? You might wonder how CSSD, which is required to start the clustered ASM instance, can be started if voting disks are stored in ASM?  This sounds like a chicken-and-egg problem: without access to the voting disks there is no CSS, hence the node cannot join the cluster. But without being part of the cluster, CSSD cannot start the ASM instance. To solve this problem the ASM disk headers have new metadata in 11.2: you can use kfed to read the header of an ASM disk containing a voting disk. The kfdhdb.vfstart and kfdhdb.vfend fields tell CSS where to find the voting file. This does not require the ASM instance to be up. Once the voting disks are located, CSS can access them and joins the cluster. What is gsdctl in RAC? list gsdctl commands in Oracle RAC? GSDCTL stands for Global Service Daemon Control, we can use gsdctl commands to start, stop, and obtain the status of the GSD service on any platform. The o