Viewing Server Performance with PerfMon and the PAL Tool - SQL Server 2012 Internals and Troubleshooting - page 291

Extracting Performance Data for a Specifi c Time Window
This technique can be useful when using PerfMon to log over many hours or days. Were a problem
to occur, for example, at 10:30 a.m. on March 15, it would be useful to extract the time frame from
10:00 to 11:00 to provide a manageable log size, without losing any data points. The command
looks as follows:
Relog Server001_LOG.blg -b 15/03/2012 10:00:00 -e 15/03/2012 11:00:00 -o
Server001_LogExtract.blg
Extracting Specifi c Performance Counters
Sometimes monitoring tools or other engineers gather logs containing extraneous counters. In these
situations, you can extract specii c counters for analysis using Relog. The Relog parameter -c enables
counters to be specii ed. In the following example only the memory-related counters would be
extracted to a newly created log i le:
Relog Server001_Log.blg -c "\Memory\*" -o Server001Memory_Log.blg
Furthermore, it is possible to perform more complex i ltering by passing Relog a text i le contain-
ing a subset of counters from the original performance log. The following command can be used to
extract those counters specii ed in i lter i le from the original log:
Relog Server001_Log.blg -cf CounterList.txt -o Server001Overview_Log.blg
The preceding example requires CounterList.txt to contain a single counter per line with the
counters to be extracted.
Converting Log Files to New Formats
PerfMon creates log i les in a binary log format (BLG) by default. In some situations it can be desir-
able to convert a performance log to a new format to enable applications other than PerfMon to
read the log. For example, this can be useful when importing the data to SQL Server or analyzing
performance in Excel. The following example shows how to convert the BLG i le to a CSV i le:
Relog Server001_Log.blg -f CSV -o Server001_Log.csv
Using LogMan
LogMan can be used to schedule the starting and stopping of logs. This can be a useful alternative
to using the Windows AT scheduler or the scheduler functions available within PerfMon. The great
benei t of using LogMan is that you can centrally control the start and stop of Performance moni-
toring. Using LogMan, it's possible to dei ne a data collector and copy that collector to multiple
servers from a single, central location. Table 10-8 summarizes the LogMan command-line actions.
The syntax is as follows:
logman [create|query|start|stop|delete|update|import|export] [options]