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

Question

Anubhav Kumar · Answer

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):
andlt;targetsandgt;
  andlt;target name="logfile" xsi:type="File"
          fileName="logs/log-${shortdate}.log"
          archiveFileName="logs/archives/log.{#}.log"
          archiveEvery="Day"
          archiveNumbering="Rolling"
          maxArchiveFiles="30"
          archiveAboveSize="10485760" /andgt;
andlt;/targetsandgt;
andlt;rulesandgt;
  andlt;logger name="*" minlevel="Info" writeTo="logfile" /andgt;
andlt;/rulesandgt;
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 andlt; DateTime.Now.AddDays(-7) || fileInfo.Length andgt; 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

Liked By

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