2.2. File System Fragmentation
Red Hat Enterprise Linux 6.4 introduces improvements to file fragmentation management in GFS2. With Red Hat Enterprise Linux 6.4, simultaneous writes result in less file fragmentation and therefore better performance for these workloads.
While there is no defragmentation tool for GFS2 on Red Hat Enterprise Linux, you can defragment individual files by identifying them with the filefrag tool, copying them to temporary files, and renaming the temporary files to replace the originals. (This procedure can also be done in versions prior to Red Hat Enterprise Linux 6.4 as long as the writing is done sequentially.)