SharePoint ULS logs Tips, Tricks, and Thoughts

ULS logs are where SharePoint logs what’s happening, they are plain text files.

Here are a few thoughts on optimizing your workflow when dealing with the ULS logs.

#1 – Know where your logs are.

In Central administration, under Monitoring->Diagnostic Logging, you can set the path for the ULS logs – this sets the path for EVERY server in your farm, so you’ll need to ensure the drive letter exists and has space on EACH server. In general, you don’t want these on the C: Drive, which unfortunately, is the default. I put them in a folder called d:\Sharepoint_Logs

#2 – Don’t log more than you need to!

ULS log files can be HUGE – on the Diagnostic Logging screen (Central admin->Monitoring->Diagnostic Logging) consider doing the following:

  • Under “Event throttling” select “All Categories” then pull the drop downs in that section to “Reset to Default”
  • Under the “Trace Log” area, set the number of days to something reasonable – Ie decide how far back you’d be willing to go to look at a problem, in many cases, 7 days should be sufficient.
  • Under the “Trace Log” area, Restrict Trace Log Disk Space – My Log drive is 80GB, but it’s also shared with a few other logs like the usage logs, and some CSV’s I generate with PowerShell – so I limit ULS logs to 40GB

#3 – Use the ULS Log Viewer.

There have been several of these types of viewers made, but there is “the one” that everyone always uses and that’s available here:

This used to be on Codeplex, but sadly, it wasn’t updated and Codeplex auto-deleted it. Todd was gracious enough to put a copy on his site so others can continue to use this great tool.

Personally, I keep a copy of the ULS Log Viewer right in the folder with the ULS logs- that way it’s nice and handy.

What the ULS logviewer does, is parse the log file and display it in a very user friendly way – I used to use Notepad++ to look at the logs and this is much much better for logviewing.  It has the option of opening a log file, or of opening the ULS logs in real time. One nice thing about it, is it seems to “Know” where your ULS logs are, so you can open the current one without having to go through a bunch of mouse clicks. It’s also great at letting you filter the logs, for example, seeing only the critical events.

#4 – PowerShell related ULS commands

There are a few PowerShell commands for the ULS logs that can be handy to know about. This MSDN page talks about all of them, below you’ll find a few that I’ve personally used with a longer explanation than whats on MSDN.


What this one does, is combines all the ULS log file entries from all the servers in your farm, and merges them down to a single file on the box where the command was run – very helpful for tracing issues between boxes on your farm.

There are a lot of ways to use the command so try get-help Merge-SPLogfile -detailed to get the finer details (In particular, note the -starttime and -endtime parameters so you are only merging managable amounts of data!)

Also a quick search found this great article by Cecildt with screenshots and lots more detail than I have here:


This command Closes the current ULS log file and starts a new one. To my knowledge it only does this on the server where you’ve run the command (ie if you have 3 servers, you’ll need to run on each one)  I’ve used this before when looking at a system in real time with a support person from MS- We ran this command to reset the log file, then recreated a problem, then ran the command again – and what we were left with was a very nice small ULS log that was reasonably timeboxed around the event we were investigating. We could have done the same with Merge-SPlogfile by setting times, but that command is slower, and we would have needed to jot down the start and end times.  In other words, New-SPlogfiles doesn’t do anything you couldn’t do with other tools, it just makes it easier under the right circumstances.

– Jack

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