During our testing on Windows Server 2012 R2, we've pushed event logs beyond the 4GB threshold without immediate system instability. However, several undocumented behaviors emerge:

# PowerShell snippet to check current log size
Get-WinEvent -ListLog * | 
Where-Object {$_.RecordCount -gt 0} | 
Select-Object LogName, FileSize, RecordCount | 
Sort-Object FileSize -Descending

The 4GB recommendation stems from EVT/EVTX file format limitations:

• Event Viewer UI may fail to display portions of oversized logs
• WEF (Windows Event Forwarding) subscriptions might drop events during peak loads
• ETW (Event Tracing for Windows) sessions experience increased latency

For WEF scenarios collecting from multiple machines, consider these alternatives:

# Configure multiple destination logs by source
New-EventLog -LogName "App1_Events" -Source "ServerA_App1"
New-EventLog -LogName "Sec2_Events" -Source "ServerB_Security"

When exceeding 4GB becomes necessary:

# Registry tweak for better large log handling
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\WMI\Autologger" 
-Name "BufferSize" -Value 1024 -Type DWord

Always combine with log rotation policies:

# Scheduled task for monthly log rotation
$action = New-ScheduledTaskAction -Execute "wevtutil.exe" 
-Argument "archive-log Security /a:Archive_$((Get-Date).ToString('yyyyMM')).evtx"
Register-ScheduledTask -TaskName "LogRotation" -Action $action 
-Trigger (New-ScheduledTaskTrigger -Monthly -At 12am)

Monitor log performance with these essentials:

# Check for log file fragmentation
wevtutil al /q | findstr /i "fragmented"

# Measure log query performance
Measure-Command {Get-WinEvent -LogName Security -MaxEvents 100000}

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While Microsoft's KB957662 recommends a 4GB maximum for Event Log sizes (particularly for pre-2008 R2 systems), modern Windows Server versions (2012 R2 and later) can technically handle larger logs. However, exceeding this threshold introduces several technical considerations:

From hands-on testing with Windows Server 2012 R2 and 2016:

• Memory Usage: No significant increase in RAM consumption observed during normal operations
• Performance Impact: Log queries may slow down when dealing with 10GB+ files
• Stability Risks: Some legacy Event Viewer utilities might crash when parsing oversized logs

For centralized logging via Windows Event Forwarding (WEF):

# PowerShell snippet to check current log settings
Get-WinEvent -ListLog * | Where-Object {$_.LogMode -eq "Circular"} | 
Select-Object LogName, MaximumSizeInBytes, RecordCount | Format-Table -AutoSize

Instead of relying on gigantic single logs:

1. Implement log rotation with archive retention
2. Consider using ETW (Event Tracing for Windows) for high-volume scenarios
3. Offload to SIEM solutions like Azure Sentinel or Splunk

If you must exceed 4GB, these registry settings help stabilize operations:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\YourLogName]
"MaxSize"=dword:1dcd6500  # 5GB in hex
"Retention"=dword:00000000
"AutoBackupLogFiles"=dword:00000001

Create a PowerShell monitoring script:

# Monitor log size and health
$log = Get-WinEvent -ListLog "Application"
$thresholdGB = 4
$currentSizeGB = [math]::Round($log.FileSize / 1GB, 2)

if ($currentSizeGB -gt $thresholdGB) {
    Write-Warning "Log size exceeded threshold: $currentSizeGB GB"
    # Add custom alerting logic here
}