- What are the differences between Oracle RAC and Oracle Grid? …
- What is cache fusion? …
- What is a split-brain? …
- What is the difference between Crash recovery and Instance recovery? …
- Explain the use of interconnect?
Oracle RAC Interview Question – Restore Voting Disk
Introduction to Oracle RAC Interview Questions and Answers
When you talk about computing related to database, Oracle RAC (Real Application Clusters) provides and support software related to high availability and clustering within the Oracle environments. By using Oracle RAC, a number of computers can access Relational Database Management System of Oracle at the same time even when they are using only a single database, thereby supporting clustering. The interconnect is used to connect multiple instances among themselves and they all work in perfect synchronization while trying to access the data. In this post, we are going to study some of the Oracle RAC Interview Questions.
Now, if you are looking for a job which is related to Oracle RAC then you need to prepare for the 2022 Oracle RAC Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important Oracle RAC Interview Questions and Answers which will help you get success in your interview.
In this 2022 Oracle RAC Interview Questions article, we shall present 10 most important and frequently used Oracle RAC interview questions. These questions are divided into two parts are as follows:
Part 1 – Oracle RAC Interview Questions (Basic)
This first part covers basic Oracle RAC Interview Questions and Answers
Answer: It is related with the miscommunication among nodes of a cluster. Those database nodes then continue their processing and make relevant changes in their data blocks on their own. In case multiple instances are responsible for modifying one block, the data blocks are not able to synchronize among themselves and those writes will be done by others for the same block. This entire process is called the split brain.
Answer: The alternate to virtual IP address is called VIP. Every node of the cluster is mapped with VIP and therefore in case of any node failure the VIP notifies the application about the node being down and itself switches towards the surviving node. In the absence of VIP, the TCP timeout would be encountered by the application. This TCP timeout then would notify a dead session as a result of the failure.
OLR or popularly known as Oracle Local Repository consists of details related to cluster and the processes related to it when the OCR is in the ASM system. The grid process takes time to start and in the meanwhile ASM system will also be unavailable and therefore an OCR local copy is booted which is eventually stored inside OLR.
Let us move to the next Oracle RAC Interview Questions.
Answer: A rolling patch refers to the cluster binaries being applied on the up and running databases of RAC environment. The cluster nodes are rolled one after another where the patched node is unavailable whereas all other instances are in open state.
Answer: This is the basic Oracle RAC Interview Question asked in an interview. The combination of data blocks coming straight from remote database caches and getting shipped to the local nodes so that the requirements for doing a transaction such as a DDL or a DML can be fulfilled.
Answer: RAC or Real Application Clusters are used to support all the software where aspects such as high availability and grouped level of clustering are expected. Other uses of RAC are:
What is the advantage of using ASM? Having ASM is the Oracle recommended storage option for RAC databases as the ASM maximizes performance by managing the storage configuration across the disks.ASM does this by distributing the database file across all of the available storage within our cluster database environment.
What is the use of cluster interconnect? Cluster interconnect is used by the Cache fusion for inter instance communication
What is Cache Fusion? Cache fusion is the mechanism to transfer the data block from memory to memory of one node to the other.If two nodes require the same block for query or update, the block must be transfered from the cache of one node to the other. RAC system must equipped with low-latency and high speed inter-connect to make it happen.
Give details on GTX0-j : The process provides transparent support for XA global transactions in a RAC environment.The database autotunes the number of these processes based on the workload of XA global transactions.
Can we use crossover cables with Oracle Clusterware interconnects? No, crossover cables are not supported with Oracle Clusterware intercnects.
Part 2 – Oracle RAC Interview Questions (Advanced)
Let us now have a look at the advanced interview questions.
Answer: There are basically two OEM tools: Database Control and Grid ControlDatabase control:
Grid control:
Answer: Md_backup is the command which can be used to take ASM metadata backup. It is also used to restore the disk group based configurations if a storage loss for ASM disk group is encountered.
Let us move to the next Oracle RAC Interview Questions.
Answer: Data blocks are shipped across a private network from a single instance to a different instance by making use of cache fusion. The data dictionary and the physical blocks are also shared by making use of interconnect.
Answer: This is the most asked Oracle RAC Interview Questions in an interview. Control files, Spfiles, Redolog file, and DataFiles are the ones present in the shared storage. Looking and monitoring the database alert log closely for the stipulated time period especially when the database was initially started up will help you determine the protocol.
Answer: “Opatch Inventory-all_nodes” is the command which will ensure that you are able to access the data of all the remotely located nodes by just a single node.
FAQ
How many nodes can Oracle RAC support?
Does Oracle RAC improve performance?
What are the major RAC wait events?
