Log Indexing and Rotation for Optimized Archival

Learning objectives
  • Learn about log indexing and search performance
  • Understand the difference between archives and backups
  • Learn about log archiving

Large enterprise network environments can accumulate terabytes of log data a day. They must store these log files either locally or in the cloud, but after several months you now have extensive amounts of log data no longer needed for production. Compliance requires that you retain backups and archives, but you also need to manage these files and rotate them to keep systems running smoothly. Indexing, rotation, and archiving are critical in log management, but we must do it properly to ensure no data is lost and the organization stays compliant.

What is Log Indexing?

To speed up log searching, we create indexes from log files and data. It’s a critical part of log management to ensure that large data silos can still be accessible and searched. If you have terabytes of data from the last few weeks and need to go back and find a specific event, indexing log files will expedite the process.

The way the logs are indexed depends on the way you configure the index. Administrators can configure indexes to ensure that they are optimized based on standard search parameters. Generally, logs are indexed based on dates and times, but we can index logs in other ways, such as categories, usernames, log IDs, and event types.

Log indexing speeds up searches, but it also organizes the data within your archives. It helps you avoid duplicates, which can be expensive when you need storage for terabytes of data, primarily if we’re storing duplicate data. Sorting and organizing logs enhance search performance, but it is also beneficial for log management tools.

Indexing tools create keys that sort log files based on configurations (e.g., by date or type), so when you search these files, the search tool returns results quickly since it can execute your query on sorted data. Of course, there is more technical background involved in indexes and organizing data, but indexing ensures that your search queries perform faster than simply having files stored randomly.

What is Log Rotation?

When archiving log data, rotation is an important concept to understand because it’s the point at which current log data passes to an archive on the system’s local storage, and we create a new log. The frequency of log rotation depends on the system, configurations, and the size of each log file. For example, if you only have a few log entries a day in a log, it might make sense to rotate logs weekly instead of daily.

The main difficulty in log rotation is moving data to an older archive file, then creating a new current file without losing any data. This process is not complicated when you have a system with low traffic, but a high-traffic system could receive several events every second. In the latter case, the system must switch from an older log file to a current one without losing data. Your system resources and log tools play a significant role in ensuring that data is not lost during this process.

Another aspect of log rotation is file compression. Most systems compress files into a .gz format so that they take up less storage space. Compression saves space, but we must extract the file data before we can read it. However, compression saves on cost and storage for unneeded files in production. It’s common for organizations to compress log files as they move from a production environment to an archive location.

What Can We Do to Optimize Log Archiving?

Every organization that handles network infrastructure and logs that track events should have an archiving solution in place. They should optimize this archiving solution for storage, compliance, speed, and reliability. In addition to optimizing for speed and costs, an archive solution should also have cybersecurity in mind. Attackers who access or archives could get plenty of information to launch attacks and potentially steal sensitive data.

It’s essential to understand the difference between a log archive and a backup. Both contain the same information but are used differently and have different functions. A file backup takes a copy of a log file and stores the duplicate in a different location. For large enterprise environments, the organization could have several copies, with one being off-site. The purpose of multiple backups is to ensure that data can be retrieved even when one backup is unavailable, corrupted, or missing data. 


Backups are a part of compliance requirements, but they also must be available quickly to recover data after an incident. The incident could be from a system failure, cybersecurity event, or a user lost a file and needs it restored. They are a part of disaster recovery, and a backup plan should be adequate. Your backup retention plan could be for two weeks or a month, but after backups are too old, they get moved to an archive.

Archives are distinct from backups because they exist as a way to store older data without deleting it. Retention plans are a part of backups and archives, but archives stay for more extended periods. The retention plan usually depends on the sensitivity of the data and compliance requirements. Archive files don’t remain on the original storage device. The old data will eventually move from its location to the new archive storage location, where it remains for as long as the retention plan indicates. Archives see use when auditing, reviewing, or investigating older data. They are compressed to save space on the target storage location.


The process of log archiving and indexing is a critical component in log management. You can store files in the cloud to reduce costs and use a SaaS solution such as LogDNA to manage output and provide a more convenient, secure, and fast answer to your log management process problems.


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