How do you periodically archive old log files based on size or date?

Ravi Vishwakarma 1115 13 May 2025

Ravi Vishwakarma

IT-Hardware & Networking

Ravi Vishwakarma is a dedicated Software Developer with a passion for crafting efficient and innovative solutions. With a keen eye for detail and years of experience, he excels in developing robust software systems that meet client needs. His expertise spans across multiple programming languages and technologies, making him a valuable asset in any software development project.

1 Answers

Anubhav Sharma 27 May 2025

To periodically archive old log files based on size or date in C#, the recommended approach is to use a logging framework like Serilog, NLog, or log4net, as they provide built-in mechanisms for log rotation and archiving.

Here’s how to achieve it with best practices:

1. Using Serilog (Recommended)

Install via NuGet:

Install-Package Serilog
Install-Package Serilog.Sinks.File

Configuration for Rolling and Archiving by Date or Size:

Log.Logger = new LoggerConfiguration()
    .WriteTo.File(
        path: "logs/log-.txt",
        rollingInterval: RollingInterval.Day,              // Rolls logs daily
        fileSizeLimitBytes: 10_000_000,                    // Rolls by size
        rollOnFileSizeLimit: true,
        retainedFileCountLimit: 30                         // Keep last 30 files
    )
    .CreateLogger();

rollingInterval: Can be Day, Hour, Minute, etc.
retainedFileCountLimit: Automatically deletes oldest files.
Log files will be named like: log-20250527.txt, log-20250528_001.txt, etc.

2. Using NLog

Install via NuGet:

Install-Package NLog
Install-Package NLog.Config

NLog Configuration (in `NLog.config`):

<targets>
  <target name="logfile" xsi:type="File"
          fileName="logs/log-${shortdate}.log"
          archiveFileName="logs/archives/log.{#}.log"
          archiveEvery="Day"
          archiveNumbering="Rolling"
          maxArchiveFiles="30"
          archiveAboveSize="10485760" />
</targets>
<rules>
  <logger name="*" minlevel="Info" writeTo="logfile" />
</rules>

Archives logs daily or when the file size exceeds 10 MB.
Automatically maintains 30 archive files.
Creates files like log-2025-05-27.log, log.1.log, etc.

3. Manual Archiving (if not using a framework)

You can implement a custom background task to archive log files:

var logDir = "logs";
var archiveDir = Path.Combine(logDir, "archive");
Directory.CreateDirectory(archiveDir);

foreach (var file in Directory.GetFiles(logDir, "*.log"))
{
    var fileInfo = new FileInfo(file);

    // Archive if older than 7 days or larger than 10 MB
    if (fileInfo.CreationTime < DateTime.Now.AddDays(-7) || fileInfo.Length > 10_000_000)
    {
        var destFile = Path.Combine(archiveDir, Path.GetFileNameWithoutExtension(file) + "-" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".zip");

        using (var archive = ZipFile.Open(destFile, ZipArchiveMode.Create))
        {
            archive.CreateEntryFromFile(file, Path.GetFileName(file));
        }

        File.Delete(file);
    }
}

Schedule this using a timer or a Windows scheduled task.

Summary

Method	Archive by	Auto Cleanup	Recommended
Serilog	Size, Date	Yes	✔️
NLog	Size, Date	Yes	✔️
Manual C# Code	Size, Date	With effort	Use only if frameworks are not allowed

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How do you periodically archive old log files based on size or date?

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1 Answers

1. Using Serilog (Recommended)

Install via NuGet:

Configuration for Rolling and Archiving by Date or Size:

2. Using NLog

Install via NuGet:

NLog Configuration (in NLog.config):

3. Manual Archiving (if not using a framework)

Summary

NLog Configuration (in `NLog.config`):