Drive selection for gmirror

[Michael Powell]

Ireneusz Pluta wrote:

> Hello,
> 
> when selecting SATA drives for gmirror, boot device, connected to an
> on-board controller, should I look for so-called "enterprise grade", or
> "raid edition" drives (like for instance
> http://www.wdc.com/en/products/products.aspx?id=40), or I should rather
> focus on models closer to "consumer grade"? Will gmirror configuration
> significantly benefit from things like TLER, or it would rather be
> harmful, like when using these disks as single ones in desktop
> applications?
> 
This is an overly broad generalization, but I would tend to match RE drives 
with expensive hardware-only RAID controllers. They are touchy and really 
designed with TLER in mind. On the other end of the spectrum is a pure 
software RAID such as gmirror. I don't know all that much about the innards 
but I believe a pure software RAID run on JBOD will work with consumer grade 
drives just fine most of the time.

The in-between caveat is the so-called 'fakeraid' sets of controllers. These 
are what you're most likely to find as a cheap 'feature-add' on a consumer 
desktop motherboard. Things like Intel RAID Matrix and such are known not to 
work well with non-Windows environments. However, much of the time these 
will still work fine if RAID functionality is turned off in BIOS and the 
connected drives are JBOD, with a pure software RAID applied instead of 
trying to utilize the motherboard BIOS RAID.

My web development server at home has a pair of Raptors on an ICH5 
controller with gmirror and has been completely trouble free for about a 
year now. I'd stay away from the "Green" drives that spin down all the time. 
Even a pure software RAID solution is likely not going to be happy with 
them.

-Mike