The post outlines the steps to take the backup (snapshot) of docker Container and restore it. Please note that this post mainly discusses committing a container as an image. This works on the container that does not use data volume. For containers with data volume, backup of the data volume must be taken separately. Taking […]
Archives for April 2018
How to mount and umount a file system in Linux
A file system residing on a SATA/PATA or SCSI device needs to be mounted manually to access it. The mount command allows the root user to manually mount a file system. The first argument of the mount command specifies the file system to mount. The second argument specifies the target directory where the file system […]
Understanding the /etc/fstab file in Linux
The file systems and their mount points in the directory tree are configured in the file /etc/fstab. This file contains 1 line with 6 fields for each mounted file system. The lines look similar to the following: Each field provides the following information for mounting the file system: Field 1. Lists the name of the […]
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 […]
How to Turn Archiving ON and OFF in Oracle database
You set a database’s initial archiving mode as part of database creation. Usually, you can use the default of NOARCHIVELOG mode at database creation because there is no need to archive the redo information generated at that time. After creating the database, you can decide whether to change from the initial archiving mode. After a […]
How to Failover a Service During Instance Shutdown Using SRVCTL
This post explains the option of srvctl to failover the service when we stop the instance. Normally Clusterware doesn’t failover any of the resources during a planned shutdown. The failover will work during unplanned outages and any srvctl shutdown is basically a planned shutdown from a Clusterware point of view. The -f option of srvctl […]
Oracle Database : How to set Environment Variables Using Srvctl
The srvctl utility can be used to set environment variables for a resource, with the “srvctl setenv” command. These environment variables are then used at resource startup. When setting an environment variable for the database with “srvctl setenv database”, it affects all the instances that belong to that database. To give a concrete example, if […]
Linux OS Service ‘smartd’
smartd is a daemon that monitors the Self-Monitoring, Analysis and Reporting Technology (SMART) system built into many ATA-3 and later ATA, IDE and SCSI-3 hard drives. The purpose of SMART is to monitor the reliability of the hard drive and predict drive failures, and to carry out different types of drive self-tests. This version of […]
Oracle SQL script to Show current Users and SQL being Executed
Purpose of the script Sample SQL script to show the following information. Who is currently logged on. If they are active, what SQL they are currently executing. How long they have been executing it. (last_call_et) The script Below is the SQL script: column status format a10 set feedback off set serveroutput on select username, sid, […]
How to Password Protect GRUB2 in Oracle Enterprise Linux 7
Why should a Linux boot loader have password protection? The following are the primary reasons for password protecting a Linux boot loader: 1. Preventing Access to Single User Mode – If an attacker can boot into single user mode, he becomes the root user. 2. Preventing Access to the GRUB Console – If the machine […]