[Beowulf] Mix different drives in RAID (WD4000YR and WD5000YS)

[Yaroslav Halchenko]

> They are both SATA-2 (3Gb/s) HDDs. With the replacement drive
well - I was more worrying about difference in seek time etc, but so far
didn't find any difference in such vital characteristics.

just now found that I was running at SATA150 instead of SATA300+NCQ (was
turned off to diagnose the problem which boiled at the end to
insufficient power supply) -- probably will enable it after some
unforeseen yet reboot of the system (I doubt that I should reset the
RAID controller on running system, though I have cache battery)

Also firmware -- good catch -- I will check it for all the drives in the
RAID ;-) might benefit from upgrade (though rule remains "not broken -
do not touch) -- I had really bad behavior with another hardware raid
after firmware upgrade -- had to downgrade to get system running

On Wed, 21 May 2008, Karen Shaeffer wrote:
> They are both SATA-2 (3Gb/s) HDDs. With the replacement drive
> at 500GB, it should work well for you. The raid controller
> will ignore that last 100GB. You need to check the firmware
> version on the replacement drive. Sometimes there are firmware
> updates that aren't well publicized. That is a common problem.
> This class of drives can usually be configured to run at
> either 1.5Gb/s or 3.0Gb/s, with a jumper on the drive. You need
> to check that. There are other optimizations available in the
> newer SATA2 implementations you might want to consider.
> http://en.wikipedia.org/wiki/Serial_ATA is a good place to
> start learning. Good luck with it.

> My advice comes without warranty of any kind. YMMV.

> Thanks,
> Karen
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