I have a question that has been puzzling me for some time ... what is the reason RedHat chose to go with btrfs rather than working with the ZFS-on-Linux folks (now OpenZFS)? Is it a licensing issue, political, etc? Although btrfs is making progress, ZFS is far more mature, has a few more stable features (especially Raid-z3) and has worked flawlessly for me on CentOS-6 and Scientific Linux-6. I used ZFS for a couple of large file servers with no problems. The only annoying part was having to manually install the kernel module each time a kernel update was issued. Because FreeBSD has built-in drivers for LSI cards (I use JBOD mode) and strong ZFS support, I've switched to FreeNAS with it's default native ZFS and driver support for LSI. I would have preferred to stick with CentOS, but FreeNAS just made things easier to manage. It also seems about twice as fast as ZFS on Linux (same hardware), but that may simply be a tuning issue. Is there any chance that a native ZFS (rather than btrfs) will ever emerge in RHEL/CentOS? Just curious, because I'd love to return to CentOS/SL next time I build large file servers. As an aside, I have used only WD Black and WD RedPro drives for RAID, and not had any issues. Green drives are scary :-) Chuck