Naming convention: Oracle 10g: FLASH Recovery Area Oracle 11g: FAST Recovery Area 1. What is a Flash Recovery Area ? The flash recovery area is an Oracle-managed directory, file system, or Automatic Storage Management disk group that provides a centralized disk location for backup and recovery files. All the files you need to completely recover a database from a media failure are part of the Flash Recovery Area. Oracle creates archived logs and flashback logs in the flash recovery area. … [Read more...] about Oracle Interview Questions – Flash Recovery Area
Interview Questions
Oracle RMAN interview questions
General RMAN Questions What is RMAN and How to configure it? RMAN is an Oracle Database client that performs backup and recovery tasks on your databases and automates the administration of your backup strategies. It greatly simplifies the dba jobs by managing the production database's backing up, restoring, and recovering database files. This tool integrates with sessions running on an Oracle database to perform a range of backup and recovery activities, including maintaining an RMAN … [Read more...] about Oracle RMAN interview questions
Oracle Interview Questions : Recovery catalog for RMAN backup
Why use a recovery catalog? The RMAN catalog has several benefits. It makes restore if all the target database is lost, including the controlfile. As that controlfile contains all backup information, the catalog would then be used to identify a controlfile backup. If an RMAN catalog is not used, the controlfile autobackup should be configured to ON. There are some features which are only supported using an RMAN catalog. Primarily the ability to store scripts which would be available to all … [Read more...] about Oracle Interview Questions : Recovery catalog for RMAN backup
Oracle Interview Questions : Grid Infrastructure Single Client Access Name (SCAN)
SCAN Concepts Single client access name (SCAN) is the virtual hostname to provide for all clients connecting to the cluster (as opposed to the VIP hostnames in 10g and 11gR1). SCAN is a domain name registered to at least one and up to three IP addresses, either in the domain name service (DNS) or the Grid Naming Service (GNS). By default, the name used as the SCAN is also the name of the cluster and must be globally unique throughout your enterprise. The default value for the SCAN is based … [Read more...] about Oracle Interview Questions : Grid Infrastructure Single Client Access Name (SCAN)
MySQL Interview Questions : Multi-source Replication in MySQL Server
Can I upgrade my slave from 5.6 to 5.7 and connect more masters to it? When upgrading so that the master version is lower/earlier than the slave version there is always a large risk it will not work. This is because newer versions may have made incompatible changes that means the older version will not be able to process or understand that change in the newer version. However, there is always a chance that it will work, but it is always recommended that if you want to go this way, attempt it … [Read more...] about MySQL Interview Questions : Multi-source Replication in MySQL Server
Linux Interview Questions – Basic File and Directory Permissions
What are Basic Linux File permissions? Linux, like UNIX, is a multi-user system, and file permissions are one way the system protects against malicious tampering. One way to gain entry when you are denied permission is to su to root. Keep in mind, whoever knows the root password has complete access. But switching to the superuser is not always convenient or recommended since it is easy to make mistakes and alter important configuration files as the superuser. All files and directories are … [Read more...] about Linux Interview Questions – Basic File and Directory Permissions
Oracle Database Interview Questions : Redo Logs and Archiving
What is the Redo Log? Redo Logs consist of two or more pre-allocated files that store all changes made to the database as they occur. Every instance of an Oracle Database has associated online redo logs to protect the database in case of an instance failure. Redo log files are filled with redo records. A redo record also called a redo entry, is made up of a group of change vectors, each of which is a description of a change made to a single block in the database. Redo entries record data … [Read more...] about Oracle Database Interview Questions : Redo Logs and Archiving
Interview Questions : Oracle 12c Multitenant Database Architecture
General CDB / PDB Concept in 12c Multitenant Architecture What is a pluggable database (PDB) in Multitenant Architecture? Pluggable Databases (PDBs) is new in Oracle Database 12c Release 1 (12.1). You can have many pluggable databases inside a single Oracle Database occurrence. Pluggable Databases are fully backwards compatible with an ordinary pre-12.1 database. Why would I consider using the Multitenant option? You should consider following Database Consolidation Goals to … [Read more...] about Interview Questions : Oracle 12c Multitenant Database Architecture
Linux Interview Questions : Open Files / Open File Descriptors
What is an open file? An open file may be a regular file, a directory, a block special file, a character special file, an executing text reference, a library, a stream or a network file. What is file descriptor? A file descriptor is a data structure used by a program to get a handle on a file. The most commonly known are: 0 for standard in 1 for standard out 2 for standard error Does the number of open files equal the number of open file descriptors? There is a difference in the … [Read more...] about Linux Interview Questions : Open Files / Open File Descriptors
Linux interview questions – Special permissions (SUID, SGID and sticky bit)
There are two special permissions that can be set on executable files: Set User ID (setuid) and Set Group ID (sgid). These permissions allow the file being executed to be executed with the privileges of the owner or the group. Similarly, there are two special permissions for directories: the sticky bit and the setgid bit. Below are few of the most commonly asked Linux interview questions on the special permissions like SUID, SGID and sticky bit. What is Set User ID (setuid)? SUID is a … [Read more...] about Linux interview questions – Special permissions (SUID, SGID and sticky bit)