This new version brings a lot of new and really cool stuff to the table:
WORM (write once read many)
Operating version for glusterd
Block device translator
Duplicate Request Cache
Server Quorum
libgfapi
VM image storage improvements – not related to QEMU integration; related to performance improvements
NFSv3 ACL support
The new QEMU integration should massively increase performance when used as backing storage for KVM virtual machines. Really nice!More info on the project's blog: http://www.gluster.org/2013/02/new-release-glusterfs-3-4alpha/