Hi, all -- I have diskfarm:~ # mdadm -D /dev/md51 | egrep /dev/ /dev/md51: 0 259 9 0 active sync /dev/sdb51 1 259 2 1 active sync /dev/sdc51 3 259 16 2 active sync /dev/sdd51 4 259 23 3 active sync /dev/sdj51 Toshiba X300 10T diskfarm:~ # smartctl -i /dev/sdb | egrep '(Model|Number|Version):' Device Model: TOSHIBA HDWR11A Serial Number: 61U0A0HQFBKG Firmware Version: 0603 drives in my disk farm, and it's about time to grow again. As I shopped around, I stumbled over a WD Red Plus 12T WD120EFBX drive at just $10 more, and who wouldn't want an extra 2T for ten bucks? So I'm contemplating rolling in a different model. But how do I know that it will fit well into the mix? The X300 is a 7200rpm 256Mcache 6G/sec CMR drive. The Red Plus is also listed as a 7200rpm* 256Mcache 6G/sec CMR drive. They certainly sound equivalent. What else do I need to consider, and where else do I need to look to learn? * The spec actually says "7200 RPM Class". Does that mean not really 7200rpm? That wouldn't surprise me in this modern day and age, and if the X300 also isn't really then that also wouldn't. TIA & HAND :-D -- David T-G See http://justpickone.org/davidtg/email/ See http://justpickone.org/davidtg/tofu.txt