Automate Backups on Linux

By Martyn Honeyford
2005-04-20

Scheduling

Our next and final task involves scheduling the execution of the backup_remote_servers.sh shell script on the offsite data storage server. We'll add two entries to the cron scheduling server to request execution of the backup script twice per day, at 3:34 am and again at 8:34 pm. On the offsite server invoke the crontab program with the edit (-e) option.

[offsite]:$ crontab -e

The crontab invokes the default editor, as specified using the VISUAL or EDITOR shell environment variables. Next, type two entries and save and close the file.
Listing 12. Crontab entries on the offsite server

34 3 * * * /home/backups/remote_db_backup.sh

   34 20 * * * /home/backups/remote_db_backup.sh

A crontab line contains two main sections, a time schedule section followed by a command section. The time schedule is divided into fields for specifying when a command should be executed:

Listing 13. Crontab format

+---- minute

                           | +----- hour

                           | | +------ day of the month

                           | | | +------ month

                           | | | | +---- day of the week

                           | | | | | +-- command to execute

                           | | | | | |

                          34 3  + + + /home/backups/remote_db_backup.sh

Tutorial Pages:
» No Excuses: do-it-Yourself, Secure, Distributed Network Backups Made Easy
» Simple Backups
» Advanced Backups
» Secure Remote Access Using Public/Private Keys
» Automating Machine Access Using SSH-Agent
» Simplifying Key Access Using Keychain
» Scripting a Backup Process
» Scheduling
» Verifying Your Backups
» Additional Security Precautions
» Conclusion
» Resources

First published by IBM DeveloperWorks

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