Database administrators work with several third-party software programs, database products, and cloud storage options every day. One of the most popular components many database administrators use is Oracle RAC. If you’re applying for database administrator jobs, then you may benefit from reviewing some common interview questions about this database product. In this article, we explain what Oracle RAC is, list eight common interview questions about this program, and share examples of professional answers.
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What is Oracle RAC?
Oracle RAC is a component that allows database administrators to install a database across multiple servers. Also known as the Oracle Real Application Cluster, this component is compatible with the Oracle 9i database and uses Oracle Clusterware as the infrastructure that binds multiple servers together. This allows them to operate as one system. Many database administrators use Oracle RAC because of its shared disk method of clustering databases, which makes it easier to scale by adding and subtracting servers as needed.
8 Oracle RAC interview questions with sample answers
Here are eight questions about Oracle RAC that you may encounter during your interview for a database administrator position and examples of how to answer them to help you prepare:
1. Can you explain what components you need to manage an Oracle RAC database?
Hiring managers may ask this question to assess how much experience you have managing databases. Highlight each key component and discuss why they’re important in your answer.
Example: “There are three primary components database administrators use. The first is the Oracle Universal Installer, which maintains the database related to the cluster. It also offers enterprise-level configuration capabilities. The second component is the database configuration assistant. I use this feature to maintain the database’s services and functionality. The last component is the database upgrade assistant, which database administrators can use to perform routine upgrades to ensure the database is compatible with the server.”
2. How does Oracle RAC differ from other database products, such as SQL Server and DB2?
Hiring managers may ask this question to determine whether you have experience working with other database products that are available on the market. Highlight a few of the key differences and share which database product you prefer to use.
Example: “Oracle RAC uses a shared disk architecture, which is a unique approach to database clustering when compared to products like SQL Server and DB2. Most other database products on the market use an architecture known as “share nothing” which partitions data. A “share nothing” architecture only grants each server access to its disk subsystem instead of providing access to the entire database, as Oracle RAC’s shared disk architecture does. This is one of the many reasons I prefer Oracle RAC’s system. The shared disk architecture makes the system more reliable and increases agility.”
3. What purpose does the VIP in Oracle RAC serve?
The VIP refers to an alternate virtual IP address that each node in a cluster uses. Discuss why assigning a VIP is important by sharing a situation where using it may be beneficial.
Example: “The VIP is extremely important in the event of node failure. When this happens, the VIP of the failed node transfers to a surviving node, which allows it to notify the application of the failure. Without this system, we wouldn’t know about the node failure until the application registers that the session isn’t live anymore.”
4. Are you familiar with the term split-brain syndrome?
Split-brain syndrome refers to a common scenario where two or more instances or nodes lose connection with each other. This has the potential to corrupt the system state. Hiring managers may ask this question to assess whether you’re capable of identifying and troubleshooting Oracle RAC issues when they arise.
Example: “This refers to a situation where instances in an Oracle RAC fail to connect through the private network. When this happens, they keep processing the data block independently instead of pinging each other, which requires each instance to acquire separate resources and may result in a corrupt system state. In the past, I’ve used Clusterware to resolve this issue. This method uses a voting disk to determine which instances or nodes to keep and which ones to evict.”
5. How do you ensure the time remains synchronized on all nodes in a cluster?
There are a few ways to answer this question. Focus on highlighting one or two of the methods you’re familiar with to help the hiring manager understand how you’d typically approach this task.
Example: “There are two methods I’ve used to accomplish this. The first is to configure the Network Time Protocol (NTP). However, if I’m working in Oracle 11gR2, I’d use the Cluster Time Synchronization Service (CTSS) to make sure all the nodes in a cluster stay synchronized.”
6. What are some of the key benefits of using Oracle RAC?
Hiring managers may ask this question to determine how familiar you are with Oracle RAC. Focus on highlighting two or three of the most significant benefits associated with using this database product.
Example: “The most notable benefit of using Oracle RAC is the scalability that using a shared disk method of clustering databases provides. This makes it simple to add or subtract servers based on a business’ needs, which lowers overhead costs. Oracle RAC also makes it easy to transfer workloads from one server to another in case of failure or technical difficulties, which provides an excellent backup option.”
7. Can you explain what grid control is?
Grid control is a tool that database administrators can access through the Oracle Enterprise Manager. To answer this question effectively, discuss the benefits of using grid control.
Example: “Oracle Enterprise Manager includes the grid control tool, which database administrators can use to deliver the centralized management system. Grid control also improves administration and configuration capabilities, which can increase efficiencies and reduce costs.”
8. Why is the load balancing advisory important?
Database administrators use the load-balancing advisory to manage applications and resources across multiple servers. Hiring managers may ask this question to assess whether you’re capable of maintaining high-quality standards. Discuss what the load balancing advisory’s primary functions are and how you can benefit from using this process.
Example: “The load balancing advisory is important because it monitors the current activities and workload of all the instances and clusters on a server. This makes it easy to see the percentage of the total workload that’s active. The load balancing advisory also equally distributes the loads across servers to improve quality.”
I hope you find this article helpful.
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