What are the performance enhancements in GFS2 as compared to GFS?

 GFS2 features  

• Better performance for heavy usage in a single directory.
• Faster synchronous I/O operations.
• Faster cached reads (no locking overhead).
• Faster direct I/O with preallocated files (provided I/O size is reasonably large, such   as     4M    blocks).
• Faster I/O operations in general.
• Faster Execution of the df command, because of faster statfs calls.
• Improved atime mode to reduce the number of write I/O operations generated by atime.
  

  When compared with GFS GFS2 supports the following features.

• Extended file attributes (xattr) the lsattr() and chattr() attribute settings via standard ioctl() calls nanosecond timestamps
• GFS2 uses less kernel memory.
• GFS2 requires no metadata generation numbers.
• Allocating GFS2 metadata does not require reads. Copies of metadata blocks in multiple journals are managed by revoking blocks from the journal before lock release.
• GFS2 includes a much simpler log manager that knows nothing about unlinked inodes or quota changes.
• The gfs2_grow and gfs2_jadd commands use locking to prevent multiple instances running at the same time.
• The ACL code has been simplified for calls like creat() and mkdir().
• Unlinked inodes, quota changes, and statfs changes are recovered without remounting the journal