I received a call on the Service Desk today from a user who reported that he only has 145GB free space left on a 500GB hard disk but he only had 170GB worth of data. He was very keen to know why the math didn’t add up.
I used a nifty little program called SpaceSniffer to work out what was taking up all that space. As you can see below the culprits were the hiberfil.sys and pagefile.sys files which were taking up 48GB and 64GB disk space respectively.
For your information, the Hyberfil.sys file is used by the operating system to store data when the computer is Hibernated. This can be deleted simply by turning off the Hibernation feature on Windows. Pagefile.sys is what the computer uses for Virtual Memory when it needs more memory in addition to the physical memory installed. In this particular case the PC had 64GB of physical RAM hence the size of the virtual memory (by default the virtual memory is the same size as the available physical memory in Windows). I was able to reduce the size to a much more acceptable 10GB.
(I also done a spot of housekeeping and ran disk cleanup and was able to salvage a few more gigabytes’ worth of disk space.)
So, all in all, SpaceSniffer proved itself to be a very handy tool indeed.