From Fedora Project Wiki
FedFS
Fedora 18 adds FedFS, a mechanism to provide a coherent namespace across multiple file servers.
/tmp on tmpfs
By default, /tmp on Fedora 18 will be on a tempfs. Storage of large temporary files should be done on /var/tmp. This will reduce the I/O generated on disks, increase SSD lifetime, save power, and improve performance of the /tmp filesystem..