The Server Room

WinDirStat - Find out what’s taking up all your disk space!

This may not be new to some, but WinDirStat is an excellent free tool for visualizing the space taken up by files on your hard disks or network drives and cleaning out clutter. I first used it a few months ago, but when one of my servers recently got worryingly low on space during a service pack install WinDirStat came to the rescue!

As you can see from the screenshot above, the program doesn’t just give you a simple bar or pie chart of your top-level directories, it also produces a view known as a Treemap. The Treemap displays a coloured rectangle for each file on your drive - larger files have larger rectangles. The rectangles are also clustered together into folders: if you look carefully at the screenshot above, there is a white rectangle surrounding about half of the treemap’s area. All files within that rectangle are inside the same parent folder (in this case “c:\program files”) You can hover your mouse over any part of the treemap and the status bar will show you which file it represents.

But why the wacky colours? The colours in the treemap represent different filetypes (determined by their filename extension) so that you can see at a glance which type of file is occupying the most disk space. Ingenious!

So how did this help my ailing server? I ran WinDirStat from a share on our network whilst logged on to the server and started a scan of the c:\ drive. A few seconds later the treemap showed up and two large files were standing out:

c:\pagefile.sys (the windows swapfile) - 1.5GB

c:\Program Files\Websense\bin\xid_trace.txt (a mystery file!) - 1GB

A bit of googling told me that xid_trace was just a logfile generated by our Web filtering software (Websense) on the servers which perform authentication (known as DC Agents). Every time a user had requested a page from the Internet, a line had been logged in xid_trace.txt to record the event (as well as our standard database logs). Ouch. I zapped the file from within WinDirStat and added it to my list of logfiles to prune periodically. If only applying service packs was so quick and painless!