Exploring PowerShell’s Export-Counter Cmdlet

Welcome back to Wahmans PowerShell blog! Today, we’re diving into the Export-Counter cmdlet — a powerful tool that lets us export performance counter data to log files in PowerShell. This is incredibly useful for monitoring, diagnostics, and performance analysis of Windows systems.

What is Export-Counter?

The Export-Counter cmdlet collects performance counter data from a sample set and exports that data to a log file. It can export the data in different formats like csv, tsv, or blg (binary log file format).

Syntax Overview

Export-Counter -Path <String> [-InputObject <PerformanceCounterSample[]>] [-FileFormat {csv | tsv | blg}]

Now let’s look at some examples, ranging from beginner to advanced use cases.

Example 1: Basic Export of Data to a BLG File

This is useful if you want a quick snapshot of system performance counters and save them in a BLG file.

# Collect CPU usage samples
$counterData = Get-Counter -Counter "\Processor(_Total)\% Processor Time" -SampleInterval 1 -MaxSamples 5

# Export the data to a BLG file
Export-Counter -InputObject $counterData -Path "C:\PerfData\cpu_usage.blg" -FileFormat BLG

Example 2: Export to CSV for Easy Analysis

Exporting to CSV format allows for easy import and analysis in Excel or Power BI.

# Collect memory usage samples
$memoryData = Get-Counter -Counter "\Memory\Available MBytes" -SampleInterval 2 -MaxSamples 5

# Export to CSV
Export-Counter -InputObject $memoryData -Path "C:\PerfData\memory_usage.csv" -FileFormat CSV

Example 3: Combine Multiple Counters in one Export

This script collects multiple performance counters and exports them together, which is great for diagnostic snapshots.

# Collect multiple counters
$counters = Get-Counter -Counter \Processor(_Total)\% Processor Time,\Memory\Available MBytes,\LogicalDisk(_Total)\% Free Space -SampleInterval 1 -MaxSamples 10

# Export to a TSV file for easy readability
Export-Counter -InputObject $counters -Path "C:\PerfData\system_snapshot.tsv" -FileFormat TSV

Example 4: Scheduled Monitoring Script with Rolling Files

This advanced scenario uses a scheduled script to collect data over time and keep logs organized by timestamp.

$timestamp = Get-Date -Format "yyyyMMdd_HHmmss"
$logFile = "C:\PerfLogs\cpu_$timestamp.blg"

# Collect CPU counter
$cpuData = Get-Counter -Counter "\Processor(_Total)\% Processor Time" -SampleInterval 5 -MaxSamples 60

# Export to timestamped file
Export-Counter -InputObject $cpuData -Path $logFile -FileFormat BLG

This script can be scheduled via Task Scheduler to run at specific intervals for continuous monitoring.

Conclusion

Export-Counter is a versatile cmdlet that makes it easy to capture, export, and analyze performance data. Whether you’re a beginner looking to understand what’s happening on your workstation or a system administrator needing automated performance logging, this cmdlet is a valuable addition to your toolbox.

Happy scripting, and I will see you in the next post!