Exchange 2013 has several performance counters running by default. While this is useful for diagnostic purposes, it also can take up a lot of disk space (can go over 1 GB a day). You can use Powershell to clear out older performance logs.

gci 'S:ExchangeLoggingDiagnosticsDailyPerformanceLogs','S:ExchangeLoggingDiagnosticsPerformanceLogsToBeProcessed' | gci -Include '*.log','*.blg' -Recurse | ? LastWriteTime -lt (Get-Date).AddDays(-7) | Remove-Item

Replace the paths to the daily performance logs and performance logs to be processed. You can also adjust the number of days it needs to keep (in the example, it's 1 week). In the example, we remove the files, but you could just as easily move them to another location if you need to.

Scheduled task

You can automate the process by having this one-liner run through a scheduled task:

Powershell.exe -Command "gci 'S:ExchangeLoggingDiagnosticsDailyPerformanceLogs','S:ExchangeLoggingDiagnosticsPerformanceLogsToBeProcessed' | gci -Include '*.log','*.blg' -Recurse | ? LastWriteTime -lt (Get-Date).AddDays(-7) | Remove-Item"