how to know a hard drive will mix well

[David T-G <davidtg-robot@justpickone.org>]

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