Host-guest file sharing is integrated with the guest page cache. Files in shared folders are cached for reading and can be written to asynchronously.
Files that are being actively written to from the guest do not experience read caching benefits. To improve performance, you can use the mount command time-to-live (ttl) option to specify the interval that the host-guest file system (hgfs) driver uses for validating file attributes.
For example, to validate attributes every 3 seconds instead of every 1 second, which is the default, use the following command.
mount -o ttl=3 -t vmhgfs .host:/sharemountpoint
Lengthening the interval involves some risk. If a process in the host modifies file attributes, the guest operating system might not get the modifications as quickly and the file can become corrupted.