Scheduling one-time jobs for Linux

Using the at Command for Scheduled Maintenance

We may need some maintenance works for our database systems. If we don't want to spend our evening with all the rebooting processes, the at command is here to help us. 

        echo "<command>" | at 22:00 Jan 18 2024

This command above runs a specific job at the desired date and time. Here's a more specific example for maintenance on a PostgreSQL database: 

        echo "yum update -y\nsystemctl stop postgresql-15.service\nreboot" | at 23:00 Jan 20 2024

We can list all jobs with the atq command. Moreover, using at -c <id>, we can check the details of scheduled commands. If a schedule was entered mistakenly, the at -r <id> command would help us remove it. 

        atq
        at -c <id>
        at -r <id>

This simple yet powerful tool can save you from staying up late for routine tasks. Use it wisely!

Comments

Post a Comment

Popular posts from this blog

Oracle Database Upgrade With OPatch Tool (RHEL/Centos/OEL)

Follow these steps to upgrade an Oracle Database using the OPatch tool: 1. Download and Prepare Files Download the patch you want to install along with the latest OPatch tool from Oracle's website. Transfer all downloaded files to the /tmp/ directory, and unzip them. Ensure the correct permissions and ownership are set: chown -R oracle:oinstall p26710464_122010_Linux-x86-64.zip chown -R oracle:oinstall p6880880_122010_Linux-x86-64.zip unzip p26710464_122010_Linux-x86-64.zip unzip p6880880_122010_Linux-x86-64.zip 2. Replace the OPatch Folder Replace the current OPatch folder inside the Oracle database files with the new one: cd $ORACLE_HOME cp -R OPatch OPatch_yedek # Backup current OPatch folder. rm -rf OPatch cp -R /tmp/Opatch . Verify the OPatch version and list applied patches: cd OPatch ./opatch lspatches 3. Check for Conflicts Navigate to the patch folder and run the following command to check for conflicts before starting the upgrade: cd /tmp/26710464/ $O...
Read more

POSTGRESQL UPGRADE WITH PG_UPGRADE UTILITY IN RHEL/CENTOS/OEL

Upgrading PostgreSQL can be a smooth process if you follow the necessary steps carefully. Below is a comprehensive guide to help you through the upgrade. Table of Contents Prerequisites Install the New PostgreSQL Version Set Up New Directories and Permissions Initialize the New Database Configure PostgreSQL Settings Stop and Disable Old PostgreSQL Services Run the Upgrade Process Finalize the Upgrade Post-Upgrade Tasks Prerequisites Before initiating the upgrade, ensure the following prerequisites are met: Internet Connection: Required for downloading packages. PostgreSQL RPM Packages: Necessary for installation. Free Disk Space: Ensure you have more free space than the current database size. Compatibility Checks: Verify PostgreSQL extension compatibility. Crontab Jobs: Identify any cron jobs related to PostgreSQL. Note: Skipping these checks may result in errors during the upgrade process. Install the New PostgreSQL Versio...
Read more

Backup Recovery Scenarios

 -----taking full backup (compressed) ------------ RUN {   ALLOCATE CHANNEL ch1 DEVICE TYPE DISK FORMAT '/backup/%U';   ALLOCATE CHANNEL ch2 DEVICE TYPE DISK FORMAT '/backup/%U';   ALLOCATE CHANNEL ch3 DEVICE TYPE DISK FORMAT '/backup/%U';   ALLOCATE CHANNEL ch4 DEVICE TYPE DISK FORMAT '/backup/%U';      BACKUP AS COMPRESSED BACKUPSET DATABASE PLUS ARCHIVELOG;      RELEASE CHANNEL ch1;   RELEASE CHANNEL ch2;   RELEASE CHANNEL ch3;   RELEASE CHANNEL ch4; } ------- some datafiles are missing, full backup available ------- rman target / sql 'startup mount'; list backup of database summary; --Buradaki tag bilgisi alınır ve restore başlatılır. RESTORE DATABASE from tag TAG20240317T180940; RECOVER DATABASE; -- RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 126 and starting SCN of 2605758 -- If you get an error like above, run the command below: recover database until sequence 126; alte...
Read more