Over recent months I've been using Vagrant and virtualised development environments.
The ease of setup and being able to exactly mirror the final deploy environment from a OS/Software perspective is, I think, invaluable
However, one little thing has been bugging me over the time I've been working with Vagrant.
After searching numerous times in vain, I finally found the solution, which I've reproduced here, but linked to the original source and the stack overflow thread so proper credit is given to the people who found/solved this issue
Basically there is an issue with Vagrant and static file serving via sendfile(), which needs to be disabled in whichever web server you are using.
Apache: EnableSendfile off nginx: sendfile: off