Software raid VS hardware raid

[Warren Block]

On Tue, 29 Jan 2013, Artem Kuchin wrote:

> My other concern is what happens when one drive goes down if we use gmirror? 
> Is it completelly transparent
> and bad drive can be hot swapped while server is running and rebuild started?
> I am thinking now about gpt+gmirror (including boot and swap)

As far a gmirror is concerned, yes, drives can be removed and new drives 
inserted while the mirror is running.  Hot swap is more of an issue with 
the hardware.  I have not tried it with SATA drives, although I think it 
should work.

The Handbook chapter on gmirror talks about the problems with GPT and 
GEOM metadata.  In short: right now, they conflict.  It's possible to 
mirror GPT partitions, but be aware that if you mirror more than one 
partition on a drive, a rebuild after replacing a drive could thrash the 
heads as mirrors are rebuilt simultaneously.

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html